I had a slow laundry standpipe a few decades/houses ago that would overflow with <1/2 gallon of water poured in. I diverted the discharge hose out a window for a few YEARS before looking into the old-school 2" cast iron trap to see what was up. I still have the screwdriver I pulled out of the pipe, but threw away the large lint art piece. The drain has worked great ever since according to the current resident.
When city water/sewer was put in there 'prior', there was a 90^ turn made by cementing 6" clay tile to the 4" CI of the original and new lines, creating a low spot that clogged easily. I could snake it from the roof thru' the 4" closet vent but got tired of the hassle. Trimming back to tidy pipe I glued up a short PVC leg between two 45s and tied them to the CI with "fernco" rubber/clamp bits. Only snaked once since from the roof and I easily slid more than half of a 100'-er thru' my repair. Judy says there hasn't been an issue since '89 when she moved in.
The house I'm in had the worst kit sink drain I'd ever seen. Pouring hot water in never did much to help, so I looked into replacing the basket strainers, trap and tailpiece. Turns out that someone had installed that cheesy accordion pipe crap and with 1/2" or more back-pitch going into the wall and raising the weir.
Relevant: the last septic I serviced had had its clay inlet 'T' shattered, apparently by ramming a snake in, but it must have been done before a remodel as the gawdawful in-slab routing/venting precluded access w/o removing the lid. The tank was a puny concrete 750 gal or less with a single chamber, so we could only re-build both in & out 'T's with PVC. I urged adding a tank vent due to lousy venting indoors, but owner balked and drains still gurgle. I surmise it's because none of the venting is right. I've never seen a snake that could harm PVC pipe (Sch-40 at least), but someone might have one of several hp, and stuff happens.
Moss, tiny electrolytics like in the video are why so many HP laptop cheapo Mobos failed. Some (6000s IIRC) were legend for just that.
