D.N.
We used to do just as you say when I was growing up. I hated doing it because we would get little cuts from the blinds. I hang my blinds (though they are vinyl) on a clothesline, spray them with a bottle of soap solution (dish soap with water and a little vinegar) and then rinse with the hose. I use a rag for any tough spots. I have also heard you can do this in the shower if you have a hose type shower head. I would think it would work just as well with aluminum blinds. If you do put the blinds ina a tub, be careful how you put them in so you can just pull them out without getting them tangled.