parquet floor adhesive problems

I am trying to glue down the odd loose block on a herringbone floor but the tongue and groove is making it difficult to lift the blocks. What is the optimum method?

Thanks

With tremendous care really. Presumably the floor has been stuck down with bitumen which has become brittle. The T&G connection between the block makes still 'fixed' blocks move and break the precarious bond there still is. You could offer up one block, you cut this one so you lift pieces of the block out without - hopefully - disturbing the neighbouring blocks.

Thank you, woodyoulike, for your help. Much appreciated.

Bilal tymms