Fun thread to read people's stories. Since Mary's Maytag is from 1951, I'm not sure if it has the heavy, cast aluminum tub or a spun aluminum tub; will have to research when Maytag switched over to the spun aluminum. Certainly a big difference in overall weight to the machine!
The cast aluminum was a Maytag standard for a lot of years; all the early models (like Brad Ross' machines) were made from cast aluminum. Sometime after WWII, Maytag switched to making spun aluminum tubs; they were more formed from sheets of aluminum. I have a 1948 Model E2LPT and that tub is cast aluminum and weighs a lot.
I've found that the softer the water you have, the less likely you are to have a stained, or darkened, tub. That aluminum is malleable and I've discovered that using hot, hot water and plain old Tide detergent keeps it looking great.
I've got a 1982 Model E2LPS (spun aluminum tub) and a couple of weekends ago, decided to use it on the patio to clean garden blue jeans and some rugs. I used Fels-Naptha, Borax, washing soda, and also Calgon water softener to make water even softer. Boy, did that tub darken!! I used the machine again the following weekend with just hot water and Tide and it brought it back to it's shine! Still trying to understand the chemical reactions to aluminum; maybe I don't want to know.
Larry's right ... it's a washing machine. Use it and have fun! You can always clean stuff up if you want it to look different!!