It will eat through polish and can ruin nails. I tend to use clear polish as glue and then apply a clear coat or two over the decoration and nail to lock it in. Experiment with layers of colors.
Many reds look regal over a coat of gold.
Silvers and metallic grays look great over black. Many opaque shades or shades with pearl-like attributes look cool over black. As usual, make sure each coat is dry before applying the next. I have never actually mixed colors together before application since it seems too messy to bother. Add depth to some shades, especially metallic colors, by alternating coats with clear polish.