One prep step most people skip. Here’s why it’s the only thing that matters for a trunk liner that stays put
- By Hatchbag Team
- Mar 20, 2026
A Hatchbag trunk liner is made to last as long as you own the car. But how well the Velcro fitting kit bonds on day one — and holds up over years of loading gear, hauling dogs, and everything else life throws in the back — comes down to a single step in the prep process.
This guide walks you through exactly what that step is, why it matters, and how to do it right from the start.
Jump to:
First Things First
Does your trunk liner even need this step? Check before you buy.
Most Hatchbag liners use a Velcro fitting kit that attaches to the plastic surfaces inside your trunk. If yours does, the prep on this page is essential — skipping it is the number one reason liners don’t hold the way they should.
A small number of models use a carpet-fit method instead, attaching directly to the trunk carpet without Velcro. Those customers don’t need this step for the liner itself.
Check your fitting instructions before you buy anything. They’ll tell you clearly which fitting method your liner uses. Not sure? Email us at [email protected] and we’ll confirm for you.
Got a tailgate cover, or thinking about adding one? You’ll need this prep regardless — even on carpet-fit cars. Tailgate surfaces are almost always plastic, and they carry the same factory coating. The process is identical.
Why Standard Cleaning Isn't Enough
Your trunk looks clean. For Velcro adhesive, it’s not.
Here’s something most people don’t know: when your car was built, every plastic surface in the trunk got a coat of silicone and wax. It’s standard factory practice — it protects the plastic and gives it a smooth, finished look. It’s also invisible, odorless, and it does not come off with regular cleaning.
Wiping the trunk down, vacuuming, even using an all-purpose cleaner — none of that removes the silicone layer. It’s bonded to the plastic at a molecular level. The only way to break it down is with a solvent specifically formulated to cut through it. That’s what Autoglym Intensive Tar Remover does.
This isn’t a cleaning problem — it’s a chemistry problem. The silicone layer is a manufacturing byproduct, not dirt. Your usual household products aren’t designed to remove it. Autoglym is.
This applies to used cars too. A lot of customers assume they can skip this step because the car is older or the trunk’s been cleaned before. The silicone doesn’t wear away over time — it was applied at the factory and it’s still there. In fact, if the previous owner used polish or protectant products in the trunk, there may be additional residue layered on top. Whether the car is brand new or ten years old, the prep is the same.
Autoglym Intensive Tar Remover is what we use in our factory in Birkenhead, England before every Velcro fitting kit ships. We’ve tested other products over the years. We keep coming back to Autoglym because it removes the silicone layer completely, leaves no residue that could interfere with the adhesive, and is safe on every trunk plastic we’ve worked with. That combination is harder to find than you’d expect.
What to Grab
Two things. That’s it.
Autoglym Intensive Tar Remover — available on Amazon. Pick it up before your liner arrives so you’re ready to install right away. Link at the bottom of this page.
Two lint-free dry cloths — one to apply the product, one to dry the surface. An old cotton t-shirt works great if you don’t have dedicated detailing cloths on hand.
The Prep Process
Seven steps. About ten minutes. One time.
Do these in order. Get this right and your liner will stay exactly where it’s supposed to — through muddy dogs, camping hauls, gear runs, and years of real use.
1. Let the trunk warm up first
Cold plastic resists solvents. If it’s winter or you’re working in a cold garage, run the car for ten minutes first, or do this prep right after a drive. Room temperature plastic makes a real difference to how well Autoglym cuts through the silicone.
→ This is the most commonly skipped step in cold weather. Don’t skip it.
2. Apply Autoglym generously to your first cloth
Don’t be stingy. You’re not detailing paint — you’re breaking down a factory-applied silicone layer. Give the cloth enough product to actually do the job.
3. Scrub the areas where the Velcro tabs will go
Really work it in. This is the single most important part of the whole process. It will not damage your car. It will, however, make the difference between a liner that holds for years and one that starts peeling up within weeks.
→ Not sure exactly where the tabs will land? Set the liner loosely in the trunk first, identify the contact points, then remove it before you start.
4. Dry with your second cloth — and keep going until you feel it drag
Here’s the test we use at the factory: when the cloth starts to drag slightly against the plastic instead of gliding across it, the silicone is gone. That drag is your signal. Dust off any loose fibers from the cloth before moving to the next step.
→ Still gliding smoothly? Silicone is still there. Go back to steps 3 and 4.
5. Test one tab before committing
Press a single Velcro tab firmly onto the prepped surface and try to peel it back. If it grips well and resists, you’re good. If it lifts too easily, run through steps 3 and 4 again — more silicone is present.
6. Install the rest of the tabs
Working somewhere cold? Warm the adhesive side of each tab gently with a hair dryer for a few seconds before pressing it down. The initial bond will be significantly stronger.
7. Leave it alone for 72 hours
The Velcro adhesive builds to full strength over three days. We know 72 hours sounds like a long wait. It’s worth it. Leave the liner in place, undisturbed, and the bond will be exactly as strong as it needs to be.
→ The hard part’s done. Let the chemistry do its thing.
Over Time
What to expect — and what to do when tabs need replacing
Our fitting kit is designed to be removable. That’s a feature, not a compromise — we want the liner to hold firmly in normal use but come out cleanly when you need it to, without leaving residue or damaging the trunk. Because of that design, the Velcro isn’t a permanent industrial bond, and over time, heat cycles and temperature swings will gradually reduce how strongly the tabs grip.
If you park in direct sun a lot, or live somewhere with significant seasonal temperature swings, you may find the tabs need replacing after a year or two. That’s completely normal — it’s not a defect in your liner. The liner is built to outlast the car. The Velcro strips are a consumable part of the fitting system, and replacement kits are available at hatchbag.us/accessories.
When you install new strips, run through the full Autoglym prep again from scratch. Cleaning products and general use rebuild silicone and wax residue on plastic surfaces over time. Skipping the prep on a replacement install is the most common reason customers run into the same problem twice.
WHY THIS PRODUCT SPECIFICALLY
Why we recommend Autoglym by name — and not just “any tar remover”
We get asked this a lot. People want to know if a cheaper generic solvent, a different brand, or something they already have in the garage will do the same job. The honest answer: we don’t know, because we’ve only tested our Velcro kits against Autoglym — and that’s exactly why we won’t recommend anything else.
Silicone solvents vary more than you’d think. Some don’t fully cut through factory coatings. Some cut through the silicone but leave their own residue behind — which causes exactly the same adhesion problem. Some products that are perfectly safe on painted surfaces can discolor or degrade the plastics found inside trunks. We’ve seen all of these failure modes from products that looked reasonable on paper.
Autoglym is what we use on every liner, in our factory, before it ships. We’ve verified it removes the silicone layer completely, leaves nothing behind, and is safe on every plastic surface we’ve tested across years of production. We’d rather give you a specific, verified recommendation than a vague “any suitable solvent” that leaves room for things to go wrong.
Where To Buy
Find it on Amazon
Order it before your liner ships so you’re set up and ready to install the day it arrives.
Amazon.com — amazon.com/dp/B01D0TXZZO — 325ml with microfiber applicator
Can’t find it? Search “Autoglym Intensive Tar Remover” on Amazon. It’s also stocked at some specialty auto detailing retailers — call ahead to check availability before making a trip.
Haven’t ordered your liner yet?
Find your vehicle and order in minutes at hatchbag.us. Grab the Autoglym at the same time — by the time your liner arrives, you’ll have everything you need to install it right on day one.
