M.A.
I've found that the best thing to help keep carpets clean is a nice length of carpet runner inside the door. It helps to get the gunk off the shoes before they hit the carpet. Taking shoes off at the door is the best. Also, have heard that al lof times that carpets getting that dirty looking that fast is because they have a lot of soap residue in them. Try getting mom's carpet machine again. Put a 1/4 cup of vinegar in the tank with the water...NO soap. See if maybe that helps. I have to agree with the suggestions about baking soda and vinegar for the tub. Added benefit is that it can help to clear out soap residue in the drains also!