The exterior of my 20 year old aluminum sided home was egged. I did not notice this until mid winter when it turned black. How do I clean the egg stain from the siding without causing damage to the siding finish?
The best solution is to use a pressure washer, but use caution because a high pressure unit can also damage the surface of the siding. The pressure washer can actually remove the paint from the surface.
It is a big expense to rent a pressure washer, so unless you have other areas (siding, patio, driveway, etc) to clean, it likely isn’t worth it. We have had some success in mixing an equal amount of vinegar, hot water, and a few drops of dish soap (1 cup of each) and soaking a thick terry towel. Hold this towel on the egg for an hour or so (a 2X4 can be leaned against the wall to hold up the towel). Agitate with a stiff scrub brush and hose down with your garden hose. This works great on auto finishes and we have had responses saying it worked from vinyl siding, however the stain was relatively fresh.