I have never really learned how to use washes. I take classes at a community college and I've seen some cool stuff come out of the kiln. When i asked how they got that effect, they said they brush on the oxide, then wipe it so it only stays in the texture.   I have tried this several times on my pieces and can't seem to get it to stay in the texture. It all washes away when I wipe it. Is my texture not deep enough? Iron not thick enough? Wrong wiping tool (we just have sponges)? Too much wate