Plastic Paint?

Plastic Paint?

I recently purchased this set second-hand: http://www.ikea.com/us/en/catalog/products/30103148 Unfortunately, the chairs were stacked when I bought them and I didn't think to unstack and check them and now I know that the seats have some paint spots that seem to be embedded in them (I can't feel it or scratch it off, it seems to have stained the plastic). I'm guessing it may not be something I can remove. So the question is, what kind of paint works on plastic, that'll last through different people sitting on the chairs, moving around, with their pants that'll rub on the seats while they sit? since the stains are in spotted form, I was thinking of buying a few colors of paint and doing sort of a splatter effect or something. Any other ideas are welcome!
What is this?

What is this?

Another new person!

Another new person!

My new place.

My new place.

new apartment.

new apartment.

Harvested for tonights dinner- the beans are bush

Harvested for tonights dinner- the beans are bush

my student apartment

my student apartment