Removing burnt-on plastic from exhausts

At the start of my recent mini Welsh tour some plastic packaging got stuck around an exhaust header — as I discovered from the smell when I stopped for a rest. To avoid too much burnt on mess I decided it was worth the risk of scratching and used a knife to carefully shave off the lumpy bits. The following morning, when then engine was cold, I used a plastic bank card to scrape off what else I could, leaving me with…

During the following 500 miles of the trip the remaining residue carbonised so when it came to deal things at home I was presented with…

To remove the barcode and other unburnt parts I tediously used cotton-wool buds dipped in methylated spirits (after protecting nearby paintwork from any splashes) and also scraped hard with an old bank card. This took about half an hour to get to this stage.

There was still a big area of lumpy plastic on the other side of that header which I scraped off with a old plastic spatula after heating the exhaust by running engine. (Plastic cooking spatulas are made from a heat resistant plastic so shouldn’t melt and add to the problem!)

Those remaining burnt on bits weren’t coming off by scraping with plastic, and using metal was bound to cause lots of damage, so it a fit of desperation I tried using Autosol metal polish with a felt polishing pad attached to a small drill. Whilst this did polish the chrome bits somewhat it didn’t touch the black parts.

Not knowing what else to do I went back to scraping with a plastic card, and to my amazement the black stuff was coming off!

So, finally, I’m now left with a header pipe that if anything looks better than the other side that didn’t get plastic on.

So the top tip to take away for all this is that to removed stubborn burnt-on bits from headers, smear area with Autosol metal polish and scrape with the edge of some stiff plastic, like an old bank card.


That’s a great result!

Yes, great job. It looks better than ever now. Are you going to do the other one anyway?

Top job. :+1:
Now you’d better get the other side polished up. :laughing:

Thanks all. The other one is mostly as good, with the odd bit of cremated insect or speck of road tar. These usually come up almost new when I do a proper bike wash and use a non-scratch scourer pad. For now, I’ve had enough of cleaning work… :slight_smile:


Have you tried Autoglym intensive tar remover. Its designed to work on paint providing its rinsed off afterwards.
Another good one for stubborn things is chewing gum remover.
Can’t beat autosol for the finishing touch

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Thanks for the tip.

If you have access to wood ash, maybe from a wood burner (?) it is amazing stuff!

Moisten some newspaper, dip it in the ash and gently rub…works a treat - I use it to clean the stove glass, oven, burnt on plastic on the actual stove as well… on burnt pans…

You kinda want an ash paste…

Not sure of the science but it creates a lye solution that’s alkaline and a great cleaner.

Must be pure wood ash only otherwise you’ll scratch stuff!!