“Sponge?”,is that an extra,I don't have one of those in my air cleaner.
As a point of interest, in the 1970’s I worked for a haulage contractor and we used to wash our “dry” air cleaner elements in a bath of soapy water using washing powder, we had several spares so always had a dry one to swap at service time.No doubt someone will come back and say that's a “no,no”,but it worked for us.