At the upscale antique shop I worked at we would wash down the insides
of musty pieces with ammonia solution (maybe a cup per gallon,
sometimes straight up if it was bad). It worked well and the ammonia
would evaporate in a short while. The only piece it wouldn't work on
was an old pine server found in some barn. Inside we found the remains
of some raccoon dissolved into the boards. Nothing would get that smell
out and it took many many coats of chellac to seal it in. Hell knows
why the customer still wanted it.