There is a product called Iron - off . They sell it at JoAnns. It comes in a tube , works great !

Dryer sheets did the job for me.

wax paper works pretty well for a lot of the sticky stuff that seems to end up on the bottom of your iron. Just fold a couple of layers and iron it, flipping it every once in a while.

There is an iron cleaner you can buy. I got mine at bed bath and beyond, it is wonderful for cleaning the sole of your iron.

This is my very belated thank you! I picked up my project again to work on it for the weekend and was able to get most of it off with the magic eraser (and a potholder mitten on my hand)!. Hopefully I'll have quilting fun again. Thank you all!