Cleaning up salt from aluminium

[mura_gadi]

Hello,

I recently purchased a $50 8" old model bintel scope, that had seen a lot of salt weathering. The focuser had large flowering lichen type spoiling etc, same for the mirror cell, brackets etc.

I tried 400 grit on a soft kitchen washing up cloth (the one with a hard plastic scour on one side). Using the soft side wetted down and the grit spread over the cloth, I managed to polish off all the aluminium flowering caused by the salt.

Due to the cloth being very soft and flexible, the result was nearly back to new across the curves without any scratching(pitting still apparent). I am assuming the grit wasn't operating at its maximum as the cloth has plenty of give.

But its a very effective way of making a flexible wet sandpaper that can be used easily on curves and corners and is surprisingly durable if your edges aren't too sharp.


PS. edited to make it a little clearer I was cleaning the parts and not the mirror.

[sil]

Last time i had to clean aluminium a wet scotchbrite was perfect then surprisingly cotton balls gave me a mirrored finish. It was the backside of solar panel plate I was building up. I didn’t have corrosion eating in and the cleanup didn’t go through the thin aluminium layer so would probably do the trick well for scope mirrors. I dont know what would be good to apply to seal the aluminium from further corrosion in future though or if you need to apply a chemical treatment to stop any ongoing reactions or if anything wont start a reaction itself. I assume the coating thickness is tiny.