You can clean a china RV toilet just as you would a household toilet, but be sure not to use caustic chemicals, such as drain openers, as they will damage the seals. SeaLand® manufactures a bowl and seal cleaner that restores shine to the bowl by removing lime build-up.
To prevent mineral deposits, periodically clean under the bowl seal. To do so, shut off the water and the ball valve open. Insert the cleaning tool into the toilet hole and close the valve, leaving the handle of the tool exposed. Hold the handle and vigorously scrub the seal all the way around. Pull out the tool, turn on the water, rinse and flush.
Seals last a long time. They do not need to be cleaned often or even on a regular schedule. “If it holds water,” Dr. Dometic advised, “then it’s working just fine.”
As part of routine maintenance, keep the seal lubricated. Simply spray the ball valve with a silicone lubricant or cooking spray (make sure the lubricant is not harmful to rubber). One quick spray will keep it lubricated and working well.