I have vinyl tiles on my kitchen floor that have not been really cleaned for some 25 years.
Scrubbing with regular soap using a hand-held, floor scrub brush has basically no effect. (I tried Simple Green, also vinegar.)
After rubbing part of one tile with "Goof-Off" (a nasty solvent) for 5-10 minutes, it looked quite clean.
I do not want to spent the time or use the amount of solvent that would be needed to clean the rest of the tiles that way.
Any suggestions? (I am willing to rent equipment, if needed.)