I just use plain old water to clean the sole plate. Here's how I was taught how to starch: when your iron gets all gunky, it's because when you’re ironing,and the fabric hasn't had a chance to absorb the starch, what you're doing is, instead of ironing the fabric, you are ironing the starch. I starch every piece of fabric I'm going to work with, at least 2 hours ahead of the time, throw it in a large ziplock bag, and let it sit, then I'll take it out, either line dry or throw in the dryer for a few minutes, then iron, have never had a problem with the iron getting all gunky then, I do spray mist with water since I don't use the steam on my iron.