2. Test a sample group, soaking them in bleach for an hour. Then compare them to an untested group of beads.
3. Test another sample group, rubbing them with lighter fluid , mineral spirits, or 
paint thinner. Then compare them to an untested group of beads.
4. Set a fourth sample group in direct sunlight for several days. Compare them to an untested group of beads
5. Test for abrasion resistance by filing the surface with a nail file. If the beads 
are coated with paint or stain, and it easily files off, you might not want to use these beads on something that might be touched or rubbed, or that will rub against clothing, etc.
6. If you're making something that will be washed or dry-cleaned, sew a few of each color of beads on a swatch of your fabric. Test by washing or dry-cleaning the swatch.
7. To test for tarnishing, mix a sample group with mayonaise and let it sit for a day or two. Rinse off the mayonaise and compare to a group of untested beads.

These tests seem like they would take some time and effort... and they do. But, if you've had the color rub off of some of the beads in a favorite necklace, as I have, then you know that sometimes it's worth the effort to test your beads.