I got a moldy enlarging lens that was easy to take apart, I cleaned it with a 50/50 mix of ammonia and hydrogen peroxide. I used cotton buds (organic cotton balls that said bleached white in peroxide).
Then after cleaning the fungus and drying with cotton balls, I did a final cleaning with denatured alcohol. Lens looks great. Coatings stayed intact but, it wasn't a Hassy, so I make no claim this will work for you. The hardest part is getting the correct spanners.
I did a ton of reading and was led to this process (the 50/50 for the fungus and denatured alcohol to get off the grease caused by the breakdown of the organisms). Seemed to work for me.