What kind of paint do you use on plastic appliance parts?
None, preferably. It's hard to find a paint that will stay on well enough for the result to be worthwhile.
What kind of paint will adhere to a plastic garbage can in a warehouse. Will any indoor or outdoor paint work where the color stays on the can?
Do a search for "plastic paint" and you will find several manufacturers of products that should allow you to recolor your sunglass frames. One of the more popular brand is Krylon Fusion, but many paint manufacturer have their own variation. There is not a huge choice of colors, but all the primaries and a few shades are covered so you should be able to find a color that suits your needs. FYI, "plastic paint" is…