1930s house tiles stained by rubber underlay

[paulharmer]

We've removed the carpet from our hall and have 1930s original tiles.
Theres a lot of discoloration and marks that are from the old rubber underlay.
We've tried HG extra strong tile cleaner and Fila PS87 Pro degreasing cleaning agent but that's seems to only get rid of the top layer of muck and not what's ingrained in.
Any ideas of chemicals to use that will bring it out

 

[foxhole]

Try lighter fuel ( pound shops stock ) on a small area first , flood , leave 30secs and wipe off with kitchen towel .