Cleaning
It is very necessary to understand that transmission by itself is of no use. If you put milk in a dirty vessel it is dirty, perhaps you cannot even drink it. If you continue to pour milk into it you are only making more and more milk useless. Instead of wasting a gallon, you are wasting two gallons, twenty gallons, two hundred gallons. The vessel must be cleaned first.
Taken from the book "A Preceptor's Guide, Vol. 2", Chapter " Augerans, France, Tuesday July 4, 1989", pg. 78, by Revered Chariji