Definitely don't use Drano because in addition to the sodium hydroxide it has a bunch of other unwanted ingredients depending upon which type of Drano product you get. For example the Drano Professional Strength Crystals Clog Remover is about half sodium nitrate and about 5% flakes of aluminum that are there mainly to put on a big show with lots of fizzing and foaming and obviously reduced effectiveness on dissolving the aluminum on the CBN wheel as well as the possibility of discoloring the wheel from residue left behind. Some of the liquid Drano products are mostly sodium hypochlorite (same thing as household laundry bleach except stronger). It would be better to get pure sodium hydroxide ... a low cost plain Jane drain cleaner called Rooto is just sodium hydroxide crystals and less than a third of the cost of Drano. There are several Rooto products ... don't get the liquid stuff because it is buffered sulfuric acid. Here is a picture of the one that you would want to get in order to get 100% sodium hydroxide.
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It's also the same chemical that I use for bleaching box elder to a snow white color.
When I was first looking for 100% lye a couple years ago, I bought a product called Insta-Flo Drain Cleaner and discovered that it was not what I wanted because it contains metallic flakes and other unwanted junk.
If it were my CBN wheel, I would just leave things alone. The aluminum isn't hurting anything and will probably eventually wear away. You're nearly as bad as I was about getting a smudge on my Robust lathe when some CA glue dripped on it.