Why do my feet get so dirty when Im in my apartment?

Go to your hardware store and tell the staff member what's happening. There will be a solution for sale to remove the previous resident's leftover coat of what-ever-it-is. Everyday solution you're using isn't going to cut it. Once you use it, you can use it all the time or try your everyday solution and see if it returns. Don't worry the cost. It will come in handy through the years as you move to new places.