I read everything I can find on enameling. And last year I found a book written in the late 1800’s. There was a chapter on keeping the studio and kiln clean. I was happy to see this as I have heard many many times how anal enamelist are.
One thing most enamelist do not like is to get oxides in their fired enamel piece. It can cause cracking and bubbles. So the best way is to keep your kiln and trivets free of these oxides. The oxidation builds up on your trivets from use. So you need to wipe them off from time to time.
I use a blow dryer every few firings and blow out the kiln. Also the enamel can building up on your trivet, you can scrap it off and add some jeweler’s rouge to prevent this. This jewelers rouge is also what you want to put on the iron if you needed to flatten you work that is warping.
I use distilled water to wash my enamels. And I look prior to using the washed enamels for spots of deterioration. These look like small white spots. And when fired will remain white spots. If you see them and pull them out usually you are okay. But as you continue to work and notice the enamels are floating on the surface, you may have to take further action.
I had a lot of trouble a couple of years ago with enameling going bad. You can throw them away and reorder. You can re-wash them all along way while using the wet enamel. To remove the floaties. This mold like substance grows on wet enamels. So they may not show up in the beginning but hours later while sitting wet. You can rinse them with nitric and water. But not your reds. One problem that arises from this is it hardens the enamel. Meaning it is now a higher fire or longer fire enamel. Which can be used to advantage if you need it.