Can polystyrene exude oil?

[The Rat]

Started in on a Novo/Frog Supermarine Attacker, and noticed it was a bit oily. Okay, wipe it down with some rubbing alcohol, too lazy to walk to the sink in the bathroom or kitchen and wash it. Still oily. Maybe it's my fingers? Wash my hands thoroughly, wash the model with dish detergent, dry it off, get back to work...

GREASEY!   

I hope that some primer will stick. 

[Dizzyfugu]

Hmm, I never had polystyrene ooze softener/plasticizer, just vinyl (of dubious quality) on an anime character kit.
I'd rather think that it might be residues of an antibaking agent (silicone?) from the moulds, this can be VERY persistent and hard to get rid of.

[The Rat]

I'll try brushing on some stynylrez in the morning. No sense dirtying an airbrush if it won't stick.

[zenrat]

I've had cheap plastic items get sticky when exposed to heat such as an Australian summers day.  I've presumed it was plasticiser leaching out of the plastic.
Never had it with models though.  Apart from tyres.
And its sticky rather than oily or greasy.
Mrs z has discovered that metho will remove the stickiness which so far (on the objects she has treated) shows no sign of coming back.

I have opened sealed A Model bags and removed very greasy feeling sprues.  I assume it was mould release agent.  I washed then in a solution containing warm water, bleach, and washing up liquid.  The paint clung onto them fine after that.

[jcf]

It's more likely residue from the lubricant used on the moving mould components: the guide pins; ejector pin assembly
etc., and the platen guide rods that parts slide on. Having worked in an injection moulding shop I can tell you that the
stuff is very greasy and tenacious. If the machines and moulds aren't properly maintained it can make a mess.

I had a Novo produced Frog-spawn that actually had a blob of greasy goo stuck in the runner at the main injection point.
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[The Rat]

Well, it's covered in masking tape now, pulling it off will be the test. If you hear violent screams coming from the area of Toronto, just have a drink for me.

[NARSES2]

Well, it's covered in masking tape now, pulling it off will be the test. If you hear violent screams coming from the area of Toronto, just have a drink for me.

Will do, indeed I'll have one in advance