Blackjack Glue

Hi All,
Getting stuck into renovating the apartment my parents own.
hasn't been touched in 15 years and is a bit like an old car, the more i get into it the more i uncover mini distasters where patches over patches over patches have been done without fixing the problem.
Anyway, to get to the point. It has floor boards under the carpet and under the kitchen lino tiles.
They are nice from what i can see under the carpet.
The lino tiles in the kitchen have been stuck down with a black glue of sorts. it looks like it has been painted on before the tiles were laid 15 years ago.
It's still sticky.
How do i get this off without ruinging the boards that it is stuck to.
Is there a solvent of some sort.
thanks for any advice.
Cheers
MP