I had a bad freon leak on my engine bay.The whole bay,is now covered with burnt on white freon stains. I tried to use a degreaser,and then power wash. Nothing worked. Any idea(s)?

My engine bay use to be very clean,but a few months ago I had a bad freon leak. The whole bay,is now covered with burnt on white freon stains. I tried to use a degreaser,and then power wash. Nothing worked. Any idea(s)? BTW; I have no way to dry clean the engine... I can't even work on my car,do to the new apartment manager & the new rules.