Hello,
I was trying to figure out a way to prevent people from selling you the wrong dirty herbs (E.g. You're buying ranarrs and they sell you guams.)
For those who don't know all dirty/grimy herbs on Old School RuneScape are just called "Herb".
This post was from 2006 but I thought it was pretty clever.
1. Get a bunch of stacks (2+) of each kind of herb, unid.
2. Then identify one from each stack, so you now know what each stack is. Then, take out an unid herb from the stacks of ranarr and above as a bank note. Then fill up the rest of your inventory with anything, like fish or anything at all.
Example:
3. If the seller is honest, their unid herbs will stack with the ones you have. If they're dishonest, they won't stack, you'll get a message saying you don't have enough space, and you'll keep your money.
Credits to "Lord_Gromit"