If you're seeing multiple in your tank, you can get some assassin snails to deal with them. Assassins don't mess with plants at all to my knowledge.
Again, Vals are sensitive to Excel, specifically glut, the active ingredient. If they're looking translucent, they could be starting to melt in response to the Excel. I think vals will adapt over time to Excel, but early melt off is expected. Someone correct me if I'm wrong.