I did a summer job when I was like 20yo, where I had to clean the sewers for a month. It wasn't that bad of a job actually. You wear protective equipment and you use the big truck to suck all of the nasty things. Apart from the smell, it's fine, nice outdoor activity for a student summer job.

After that, things like wet food in the kitchen sink or hair in the shower drain didn't cause me any issue. If it's actually dirty, just wear rubber gloves. Wet food from the sink is nothing, you can use your bare hands and rince.