That's a Bummer for sure. What I use to clean the aluminum gutter on the house is "Awesome" spray bottle from the dollar store (for $1) and the bleach sponges from Mr. Clean but you can also get the off brand at the dollar store or even Wally World. I assume your aluminum is painted as are gutters but try a small section just as a test. My gutters come out sparkling clean and it doesn't take much elbow grease to get them that way. Hope this might help you out. If you're going to do this in the sun, spray on the Awesome but don't let it dry. Have the bleach sponge wet and ready and just wipe back and forth. Spray off with "SOFT WATER" and you should be good to go.
Steve & Sally / HiTee & Hudson Our Little Poms / Heidi & Houston Forever in our Hearts
04 NEWMAR MACA 3778 W22 / 05 PT Vert
Michigan (Summer) Florida (Winter)