I signed up for Tetys today and when I got here found it in a state I didn’t recognize (and don’t know how to clean safely), so I left it alone and used Dione.
This looks like resin that needs to be cleaned up. By the wall, you’ll find instructions on how to clean the resin tank, or you can use this link provided. Please make sure not to use a metal spatula when cleaning the tank, as it could puncture the plastic layer.