This is not strictly knitting related, but I'm hoping some of you may be able to help me out:
I have some natural yarn that I want to dye and I want to dye it with old coffee grounds. For the past few weeks I've religiously put the used grounds from my espresso machine into a glass jar, where they usually manage to dry pretty well out before the next batch is added (usually the next day). A few days ago I noticed some mold in the lower reaches of the grounds pile and when I poured it out of the jar I saw that there was quite a lot of mold growing in there.
I'm pretty sure I don't want to dye with moldy grounds, so my question is: What's the best way to store the grounds between brewing and dyeing?? Should they be spread out and allowed to thoroughly dry or should I brew a giant pot of coffee all in one go and use the grounds for dyeing immediately after they've been used for brewing? Or should I do something entirely different??