Can I reuse the same stir stick that I used a week ago if there is still some dried on leftover resin on it? What about a plastic measuring cup? With the cup, I understand the issue that leftover resin could mess up the measurements when pouring in new resin, but other than that issue I’m just trying to understand the risks of reuse? (I assume the old resin is so hard that it won’t come off in the new mixture). Thanks