So, I meal prep, and I use bowls like this to carry my prepped lunches to work:
From another angle, showing the lip below the lid:
The recycling mark on the bottom says they are polypropylene for the bowl and polyethylene for the lid.
I leave the empty bowls in the office dish-washer and then take the clean bowls home whenever the dishwasher's been run. Due to forgetfulness on my and my coworkers' parts, I have occasionally found myself trying to figure out how many of the stack of bowls on the break room side table belong to me.
To rectify this problem, I have this idea for a design based on my initials that I'd like to work on the bowls I use to carry my lunches so I can identify the ones that I brought to the office.
So, is there a dishwasher-proof way to make a mark on polyethylene or polypropylene?