I repaired a broken seat hump today (one side was smashed off by Royal Mail). When cleaning the paintwork with acetone prior to gluing the strengthening pieces in, I was surprised to find blue paint appearing on the cleaning cloth. A bit of experimentation later revealed that if the surface has been treated (all the polished shiny bits), there's no problem. If the surface has been left unfinished (e.g. under the seat hump) then acetone lifts the paint. Anything to save a penny, eh, BMW?

bugga of a way to find out Dai

good luck mate

It didn't do any real damage Charlie - it was just a bit of an unwelcome surprise. It looks like BMW really went to town on the penny-pinching in the out-of-sight places. Especially the back end.

Oh yes, acetone is a solvent. It is also used as a degreaser prior to repainting.

@Dai wrote:I repaired a broken seat hump today (one side was smashed off by Royal Mail). When cleaning the paintwork with acetone prior to gluing the strengthening pieces in, I was surprised to find blue paint appearing on the cleaning cloth. A bit of experimentation later revealed that if the surface has been treated (all the polished shiny bits), there's no problem. If the surface has been left unfinished (e.g. under the seat hump) then acetone lifts the paint. Anything to save a penny, eh, BMW?

Gees I wouldn't touch any paint with acetone regardless of what it had been treated with, that's asking for trouble.

acetone is a very effective paint remover.... and is often sold as nail polish remover.
get yourself some wax and grease remover..... prepsol

Rubbing alcohol (isopropyl) from the drug store works great and doesn't mess up paint.  It's cheap too.  Get 70% or stronger.

I'm going back to the eight litres of brake cleaner that's stored next to the acetone. The acetone is now reserved for degreasing metals only. And cleaning sh!te off my workbench.