Below are a copule of 2009 posts by Tony Athens. The bottom post was a response to a question on a QSC.
For what it's worth,
Tony Athens: Circulating a 10:1 mix of HCL thru the raw water side of your engine for a few hours to overnight can do a very good job--Remove all the zincs first--RYDLYME (Google it) does the same thing and has a good web site and supoport that will also do an 1st class job.. Same stuff with some perfume.. Tony
Tony Athens: Frank, I am not exactly sure what you did but NEXT time ,( and for others), NEVER use acid of any type on the air or fin side of the after cooler.. And when you do use HCL, mix 10:1 with water.. Use it only on the salt water side--cap one end, stand it up and fill up the tubes--takes about 20-30 minutes to do a real good job removing calcium, etc., from the ID of the tubes after a mechanical cleaning with a rod to remove the big pieces........ The fins are very delicate ( very thin) and pure copper does not do well in straight HCL, and even at 10:1 unless it was soaked for a short time which can be marginally OK to remove surface crud only.. Most reading you do with HCL and copper may say different, but I also do not think most writings on this subject does not take into account that we are talking .020"-.030" thick copper foil and solder and/ or roller forming to end caps of an unknown alloy or quality.. Keeping it (10:1 or using something like Rydlyme) in the Cu-Ni tubes only, does has no potential bad side effects. After that we always use soda ash with water for the 100% neutralization of the core/crevices, etc... Cleaning the air side should normally be done with a solvent or spray brake cleaner when really oily and followed up with a serious rinse with some type of water based cleaner with hot water, and/or Ultrasonic cleaning................ As to the silicone strips, an engineerÂ´s wet dream at best.. If and when I catch my breath, IÂ´ll add a bunch to my aftercooler maintenance article and bring it up to date... Tony