What's the best way to trim a pet's nails if they're black and you can't see the quick?

Trim small amounts at a time and look for a chalky white ring indicating you're nearing the quick. If unsure, trim just the tip of the nail to avoid cutting into the quick. Using a nail grinder can offer more control and reduce the risk of cutting too short. If you're uncomfortable, seek help from a professional groomer or vet.