[euromodder]

In a past life I used to build models.

Acrylics should come off with oven cleaner though there are a few issues.

- Oven cleaner isn't what it used to be due to health regulations, it's now far weaker stuff and less suitable for paint removal (less caustic soda in there).
Put the parts in a plastic bag, spray, seal the bag, let it sit overnight.

- Caustic soda dissolved in hot water should do the trick - let it cool down to no more than lukewarm before putting the model in it, or the plastic will warp.
(Gloves, eye and breathing protection highly advised when handling and dissolving solid caustic soda ! From a former employment, I recall a delivery driver being hospitalized after getting a single chip of caustic soda in his shoe, he didn't realize it until hours after the delivery. Nasty stuff.)

- IPA or iso-propyl-alcohol is a good thinner for acrylics, soaking the model in IPA will weaken the old paint.
(Cover the container containing the IPA and model with something that seals it off or the IPA will evaporate quickly - not too healthy either.
Note : so-called rubbing alcohol may contain ether which will attack the plastic - check the ingredients before using on plastic.)