Hi, thanks to the two replies last time when I posted the question about cleaning the scale buildup on ceramics by using vinegar. I tried, and the lightly scaled ceramics work perfectly, but the very tough scale was not really afraid of the vinegar, LOL Are there tips for cleaning the tough ones, such as the length of time of soaking prior to cleaning, straight vinegar or certain ratio of diluted vinegar, and the materials to scrub, etc??????

Thanks