On Jun 9, 8:13*pm, "The Henchman" wrote:
Concrete sub-floor, no backer board. *40 year old 4 x 3 tiles with yellow
"mastic" as the adhesive. * It's caked on good underneath and it's old. * *I
wanna prevent renting a Hilti/Kango with a scrapper cause it'll cost $100
around these parts for a day. *That'll be a last resort I guess

Solvents?

And type of manual scrapers?

grinders or some other abrasive?

I can't damage the sub-floor (concrete) underneath.

Can you just go over it with new backer and ner tile/wood/carpet????