How to clean?

[YYS4BOB]

I've used Meths & Surgical Spirit in the past to remove adhesive residue from boxes as well as to de-grease models.

[Diecastmolester]

I made the mistake and soaked plastic parts in alcohol.
The result was so depressing that I didn't even photograph it. Straight in the bin. Lesson learned.

Mind you, this is only true for acetate plastics. Styrene plastics will not be harmed by alcohol.
Make sure you can tell the difference between the two before you let alcohol get near plastics.

[Idris]

Mind you, this is only true for acetate plastics. Styrene plastics will not be harmed by alcohol.

If memory serves, styrene plastics are attacked by acetone (aka nail-varnish remover).

[Squid]

Acetone can also have detrimental effects on certain paints. I keep that stuff away from my models.

[Diecastmolester]

Mind you, this is only true for acetate plastics. Styrene plastics will not be harmed by alcohol.

If memory serves, styrene plastics are attacked by acetone (aka nail-varnish remover).

Correct. Acetone eats styrene, alcohol acetate.

[lionel-honda]

I also use warm water, apply some liquid soap to a soft toothbrush and lightly scrub the entire toy. I generally avoid all decals and brush very lightly on silver painted trim parts. I use compressed air to remove all water from crevices and axels/wheels.If the paint has small blemishes or light scratches, I will lightly apply and rub in a small amount of automotive scratch removal compound. After this is all done, I buff with a clean micro fibre towel.
The task of cleaning models after buying a childhood collection is therapeutic for me and one of my favorite parts of this hobby. I can’t tell you how many grungy and rough-looking models I have transformed into near-mint models just by using the method above.

Scott

[Diecastmolester]

Unfortunately I have no 'before' photos, but this arrived filthy, dusty and looked bad enough to be considered a resto candidate.
This is what it looks like after getting pretty much the treatment described by Scott and a rub down with olive oil afterwards.

[lionel-honda]

It looks amazing! Therapeutic.....right?

[Diecastmolester]

Oh totally. I can do this all day long.
It also gives me that warm fuzzy feeling I'm creating value with my work, even if that is largely imaginary.

[Squid]

I've done a few tests with acetone and a modern Hot Wheels car. Thus far, I haven't noticed any ill effects on the interior or the paint (though acetone does a bang-up job of removing tampo printing). I mentioned earlier that acetone can attack some paint...the paint in question was early Hot Wheels "Spectraflame," and I'm pretty sure that's a lacquer. Bottom line: test out chemicals on a junker first.