What do people here find the best way to clean their flasks etc after using them to make starters? I find i end up with a ring of gunk that doesn't just soak off. I've thought of using brushes, or dishwasher powder, but don't want to scratch or pit the glass at all or create anything that nasties could live in.
Are bottle brushes fine to use? Or should i stick with sodium percarbonate?
Are bottle brushes fine to use? Or should i stick with sodium percarbonate?