Sticky residue from vinyl floor tiles

[dummer]

Hi All - I've looked to see if my question has been raised before and I can't see it, so............I have taken up some vinyl floor tiles from the bathroom. I had to use the heat gun to soften them up or they would just crack and come up in tiny pieces.
Question is - any ideas on how to remove the really sticky black adhesive residue that's left on the floor? I will have vinyl floor covering put down when it is sorted, but I cannot imagine a fitter being able to lay vinyl on such a sticky floor.
I've tried white spirit without success. Any suggestions would be most welcome. Thanks.

 

[mack4]

You don't say if you have a concrete subfloor or, chipboard/ floorboards.I'm guessing it's concrete coz of the 'black' adhesive.If I'm correct your flooring guy will have to lay some self-levelling screed in preparation for the top covering.If it is a timber subfloor just lay plywood over it, nailed @ 150mm centres.
mack