wrote:

It's not vinyl;

It probably is.

The old stuff was called VA tile. Now it is just called vinyl
tile.

I take it off with a scraper.

I just removed some glued down on a cement floor.
No scraper would touch them. I tried.

I ended up using a heat gun.
It was a long hard job.

Using heat like that is what usually causes a place to burn down.

You (and the OP) should use this:

===========
http://www.tiletool.net/Floor_Scrapers.asp
http://www.tiletool.net/700.gif

Tile Floor Strippers removes vinyl tile and ceramic tile tiles faster
and easier than ever before with one our tile strippers. These units are
very portable and make quick work of any tile removal job 3/4" HP - 110
volt motor. Cam-driven oscillating blade — no belts or pulleys.
Adjustable for many jobs. Blade not included.
==========

Rent one.

I've seen something at home despot that's about the size of a tool box
on wheels with a handle that I think is heavy and has a blade for
scraping floors. I can't find a picture of it anywhere on the net, but
it might also be for scraping tile (a non-powered manual scraper).