I removed it just like is beeing suggested, then I burned it with a small propane bottle attached to a torch: be careful not to stay too long in the same place; then use a wire brush and semove all that black soot; clean with aceton aftewards
In my case, I replaced all that smelly mouldy carpet with furring strips every 2 feet or so, then got sheets of foam insulation (the ones that are sold at Home Depot for about $ 8.00 for a very large sheet; then I used aromatic cedar panels ( I get them here in Houston from someone I know for about $4.00 a piece ( 4 inches x 8 feet, tongue in groove), so for abot $100.00 I did my entire boat (Hunter 33 - 1982)
That was the best thing I doid: mould does not like cedar, not insects, I left it eaw, so it still smells nice, 18 months after I did it