I don’t have that problem. The things I do are: Not to have it cocked so there’s no salt in the chamber and I lay it on its side under my coffee table away from sunlight. Laying it on the side prevents it from entering the hole. I use Aldi’s table salt and I don’t know if it’s different from the Coles table salt. I wouldn’t put anything else in there. I hope that helps.

Edit: Maybe try decanting some salt in a jar and throw some silica packets in there and only use that for your gun.