Melting PU foam

I know its not oftern that I post a question here but I havnt a clue on this one so im looking for some inspiration!

Does anone know a chemical that I can use to melt PU foam from the centre on a moulding? Imagion I have a fibreglass box that has a PU foam core that I need to remove from the middle.
The foam is the builders type PU foam that comes in a squirty can! the part was origionally made in several pieces that were bonded together, but received some damage and as a quick fix someone filled it with foam to keep it in service!

Thanks in advance!

I am not aware of any healthy solutions. Perhaps MEK or methylene chloride.