What's the right word for (cleaning) or (separate the bad ones from good ones) especially when for example you need to cut the long stems short, or take the weeds off them,...etc.?! .....Pick up?!
You can sort (separate the good from the bad), trim (cut the bits off you don't want), and wash/clean. there will be other possibilities.
A more general word that covers all - preparation (for cooking or for selling)
not a teacher
I agree with tedtmc: prepare. We often shortened the verb to 'prep' and at the time when I was in MA (U.S.) we served 1500 vegetarian meals a day 49 weeks a year. Today, they're probably serving more but I'll bet the term 'veggi(e) prep' is still being used.
I agree - preparation would cover almost all eventualities - sorting, cleaning, peeling, scrubbing, washing, as well as chopping, cutting, slicing, dicing etc etc.