For a fast clean of the window, make a clip which will hold a saphire (or glass) plate in front of your existing window. Clean the Cu with HCl (obtained at Safeway to adjust pool pH). Rinse in water for 5 minutes. Put back. All done in 10 minutes and can be done in a fumehood with no exposure to fumes. Don’t care about the stainless since you remove the plate from the system or cleaning.
