To answer the second part of your question while branching into the first, there is a good response from /u/Aerindir in this thread from the FAQ section on Trimming Nails:

• How did people of older civilizations cut their finger/toe nails?

If you want to know more about prehistoric nail clipping and grooming, I would recommend posing the question at /r/AskAnthropology as they have more specialists on prehistoric peoples.