Sorry just been O/S and just saw your reply re carpet cleaner.
I would think that the proportion of methylene chloride would be quite small as it is not good for materials e.g I think nylon.
By law for most consumer products the ingredient listing if it is shown has to list the raw materials in proportion with the largest concentration first. Normally this would be water (or aqua) and then in diminishing concentration. Once the level is below 1% the ingredients can be listed in any order. That is why you may see colour or perfume at the end of the listing.
Not sure which brand it is and whether it has an ingredient listing or not so hard to know.
Most carpet cleaners will have some solvents in them that should not be bad for trim. You can always use the old tried and true method of sunlight soap or other pure soap in flake form and then dissolve and lightly scrub or dab. This is a wet method however and you will have to dry it afterwards.
I have downloaded the Material Safety Data Sheet for SEM Bumper Cleaner in liquid not aerosol form. This is available here.
http://www.semproducts.com/product-catalog/specialty-products/urethane-bumper-stripper/
Its active ingredient is dichloromethane which is the correct term for methylene chloride. It is 70-100% methlylene chloride, 10% propanol better known as "rubbing alcohol" the stuff they swab you with before getting an injection and some solvent.
if this hasn't worked and did not damage the plastic then it might be worth trying something more aggressive. It looks like it works on polyurethane bumpers, but I am not sure whether all bumpers are made of it or some are plastic. You can always try some rubbish plastic lying around to see if it is affected.
Brake fluid is normally a good paint stripper. It used to made up of acetate esters such as butyl acetate from memory. This is a similar material to some types of nail polish remover. I would think that any residue would be easily removed with the normal paint cleaners like prepsol as the ingredients are similar solvents.
If there is a hidden spot that will not show I would try:
1. Brake fluid
2. Acetone based nail polish remover - not the herbal stuff. The problem with this is that it may remove the paint, but also affect the underlying surface. Try it out but don't leave it on for too long. It might be worth just using a rag dipped in the solvent and rubbing a hidded spot to see what it does.
The only other solvent which is really aggressive is MEK or methyl ethyl ketone. It is used in the printing inks industry and we use it at work to remove printing off plastic bottles i.e we code our plastic bottles with an ink and sometimes get it wrong and have to remove it. Most polyethylene and polypropylene bottles get crazed if you leave it on too long, but a quick wipe is normally ok. MEK is a nasty solvent and you would need to have a lot of fresh air or preferably a cannister (not paper) mask when you use it.
It is very unlikely turps, metho or even white spirits or petrol would work either.
