Hey guys. So when I clean my vaporizer tubing, I soak it in rubbing alcohol to make oil with the resin. I do this with both my whip and balloon attachments. However, the past two times that I’ve cleaned my balloon tubing, I’ve been left with this strange, yellowish brown stain on the tubing. I washed my whip at the same time without getting the stain. Here’s a picture…any ideas on what it could be/if it is safe to vape with?