For rust removal: Barkeeper's Friend, made into a paste and applied with a rag, old toothbrush, or a steel or brass brush. It's about $2 a can at the supermarket. I make the paste in a recycled tuna can.

For cleaning grease: a spray cleaner called Awesome works well and is sold at the dollar store. My wife's shoe store has Canadian customers who stock up on Awesome when they visit Michigan because the same product costs $7-$8 in Ontario.