Have you ever heard of a fat log, or a soap log?
20 or 30 years ago, drains were backing up for some of my n'bors and the plumber or someone came out, went into the manhole, cleaned it out and said we had a fat log, or maybe a soap log?
Caused by people letting food grease go down the sink. Sometimes it's washed away but sometimes it builds up.
Finally, another n'bor had a clogged sewer line and I dcided to google those terms and there is nothing there.
Maybe one word was log and the other word I've forgotten?