You can kill the mould with heat. Some types can also be killed by cold, although some just go dormant with cold. You could surface clean the pads, then, if you can get access to one, put the whole sax in an autoclave. Set the temperature at about 65 centigrade and it will kill the mould. If the autoclave does not have a variable setting, don't use it. The sort used in doctors and dentists usually run at 120 centigrade, which could cause a disaster.
You can also - and I can barely believe I'm even suggesting this - use a domestic electric oven, as long as it has a glass door. If you do this and it all goes wrong DON'T BLAME ME! You will need an oven you can trust and an accurate oven thermometer. Put the oven on, at as low a temperature as possible. Monitor it using the thermometer. When it gets to 65 centigrade, leave it along for half an hour. Check it is still at the same temperature. Wish yourself good luck and put the sax in. Leave the oven thermometer near the door so you can see it through the glass. Give it half an hour. Do not, under any circumstances, let it get any hotter than this, or all the shellac will melt and you'll definitely need a repad. Shellac melts at between about 75 and 120 depending on type. So don't let it get any hotter than 65 to allow a margin for error.
You'll probably need to re-oil the keywork as the heat may make the oil sticky.
If you do this, and it all goes well you'll kill the spores and it won't cost you anything. Get the heat too low, and you won't do any good. Get it too high and you'll have a disaster. It's the sort of thing I'd risk on an old knacker of a sax, but only then if I was very careful. On a YAS275? Maybe. Depends on how much you paid for it, the cost of a repad and what sort of condition the rest of the sax is in.
Is this the most lunatic suggestion for how to treat a sax in the whole history of time? Maybe.
Jon
