The package on those warns not to use them where you store food... so, I wouldn't use them that late. I had mites during flower a while ago, and I used the iso alcohol/water (50/50) in a spray bottle. I only had the mites showing up on a few leaves here and there - never saw any on the buds luckily. So, I'd spray leaves carefully everytime I saw any sign of them (trying my best not to spray buds). The alcohol makes the spray evaporate very quickly, so I assumed that it wouldn't bring on any mold or anything. It worked out pretty well for me... no mold, and kept them at bay - but didn't totally get rid of them (it only kills the mites, not the eggs).