GMS v110 - Mapleversary

So i'm trying to get some of those new medals. Two of them are:

Pick Up Artist - Sell 1,000 items to an NPC vendor in one online session.
Antienviromentalist - Discard 500 items.

In both cases I tried selling and discarding potions, arrows, etc and equip but got nothing.

Anyone has any idea what am I doing wrong?

EDIT:
OK! After a very long a tiring day of researching I figured out how to get the Antienviromentalist medal - drop 500 UNTRADEABLE items.
If you want an easy way to do it and you don't have a pet to pick up junk for you, go to Kinoko Shire. You can buy 500 food items there which are untradeable for 1,800 each.

The second medal i'm trying to get is this one. The Pick Up Artist medal.
I tried selling 1,000 of the above mentioned food items (which are untradable, but sellable!), but nothing.

I Seriously have no idea what I didn't try so far. I'm starting to believe this medal is bugged.

You can buy an untradeable key in Elluel for 500 each.