Liquid Tide laundry
detergent should do it. It will even take off cosmoline when used with hot water
. You can find all kinds of "eco friendly" solvents sold in auto parts
stores that will say if they are safe for aluminum
, but Liquid Tide should be readily available and it will clean off any other crud that is in there. You may need a bag of pipe cleaners or a pressure sprayer, the kind used to spray weed killer, to really get in between the fins.
Pulling a system apart means more than recharging it. You need to apply a high vacuum first to empty it out (illegal to just open it up and dump the gas), then also be concerned about proper seals
, not just recharging it. And apply vacuum again before recharging. A project
to be avoided at all costs if the system is working.