These wood floors are over 100 years old, covered in paint spills/splatters, dirt, and hidden by carpet for over 25 years. Sanding is not the best option in this case so I'm into a big DIY of stripping the varnish and paint with chemicals and hand tools. The end result is very satisfying.

Poly for floors for my final new protective coat. https://amzn.to/3uStmFw
Zep stripper: https://amzn.to/3hDtaGW