I have a jar of plum alcohol that it is forming mold already due to the uncovered area not being filled with alcohol again. So would like to know what is the best use of it such as the possibility of making fertiliser for planting or can only discard it?
Yes, (it is eligible to) put it into the compost bin. Because Mold is actually an agent of composting. Moldy food is food that has partly composted.
This answer is found here by and credit to John Jayne.
Simple yet precise so I quote his words with a little bit of words adding.