"I couldn't just stand by and let these objects, damaged or not, simply be destroyed so I asked him not to throw them away," Gatt said.
The recordings were passed to Gatt's business partner, Louis Hoover, himself a singer and a regular headliner at jazz venue Ronnie Scott's.
Hoover, said: "When I saw the labels and footnotes on the tapes, I could not believe my eyes, but then when I saw how severely water damaged they were, it was gut-wrenching. There was literally plasticised gunk oozing from every inch."
A music industry contact of Hoover pointed the partners in the direction of Martin Nichols, a sound technician specialist. Nichols, of White House Studios in Somerset then painstakingly restored the tapes, cleaning them over a year.
"I should've turned round and said 'no thank you'. They were covered in mould, looked really tatty and had clearly suffered a lot of water damage," Nichols said. "They should've been binned, but the end result really surprised me because they're now very high quality."
It is hoped the recordings will now be released in vinyl, CD and downloadable versions.