What exactly do you want to do with them? Do you want them to be for inside or out? You could paint some plain yogurt on the side and make a mossy patina. There are all sorts of things to do with them. Good luck!

If you use latex on clay pots, you might want to put a sealant coat on top to help it last a little longer.

If they're plastic pots, you need a special paint that adheres to plastic.

Have fun!