I flushed my system components with some non-industrial flushes and I lost a new remanufactured compressor due to debris that wasn't removed. Decided to try TSI and thought a gallon was over-kill. It wasn't. The debris flushed from the system components salvageable was beyond my worst nightmares.
A gallon was fully used and each component was flushed and re-flushed until the solvent came out white.
Expensive, yes but worth the money to know that each component is clean and internally dry.