I am not sure if this question is a valid question as far as the Help Centre rules go.

I have recently purchased a used flute (Trevor James Cantabile) which comes with a hard case and a soft case. The instrument itself is fine, and so is the hard case, but the soft case suffered some "damage" in the form of mould (I can see some white spots on the outside, and I can smell it on the internal "fluffy" material, but it's white, so I can't really see it).

I am not sure what the material is exactly, and there is no label with washing symbols or instructions, so I was wondering what the proper way of cleaning such a case (including mould) would be. The instrument was stored properly, it's just the particularities of the climate here that really affect fabrics (and leathers) if they are not ventilated properly.

This question is not for this specific problem only, I would generally like to know how soft/demisoft cases for brass/woodwind instruments (possibly other instruments too?) should be maintained and washed, so that the materials are not ruined and the instrument is not ruined either.

I am pretty certain the industry uses some standard materials that would help identify a one-fit-all algorithm, more or less, but I do not know how to clarify my query well enough or where to look.