Yea I know the description is really unclear. I tried to cram too much information on one screen, but after the jam voting ends i'm planing on realeasing a new build that has clearer instructions.
I did have a plan for making an effect for substances dissapearing but i forgot about it and realized it too late :P again, I plan to add that in a new build.
The "accidents" where you can move the container a bit and destroying the substance in the process annoyed me a lot as well, I just didn't implement the fix yet. (will probably place the substance further away upon removal)
Thanks for the detailed feedback I'll make sure to put some improvements into the game :D