I have a 100 year old house. In the 50's or 60's some genius installed block tile using black mastic directly over oak hardwood. The tiles come up ealily as does some of the mastic, but some of the mastic is hard to remove. I read in an earlier post that sanding will remove the glue, but a. I have a hall and three rooms to work on and I want to wait until all are finished before sanding. b. Based on the age the mastic probably contains asbestus and I do not want to turn it into dust.

I have been told that I could use one of the "orange based" cleaning solutions which I did in this photo. It took over an hour of cleaning for this small are and there is still mastic remaining.

What is the best way to remove it without damaging the floors?

I have tried to attach a jpg file photo but keep receiving the messaage that it is not a valid image file.

Thank you.