Just throw some dishwasher detergent down there once a month. It’ll be fine.

I once cut out a piece of pipe in some guys home, because it was all fucked. The pipe was suuuuper heavy and upon inspection it looked like someone poured concrete down there. It was very hard to clean, the guy had to hammer on it while having a pressure washer wash it out. As it turns out, his wife used multiple washing tabs in the machine to make it extra clean. She did that for over a decade.