Hello,
Im not sure if the bug is still possible to use.
But here it is.
There are quests where you have to collect some items.
Im taking ghost bug eggs as example.
You need 200 ghost bug eggs and can do the quest 3 times.
First get 200 ghost bug eggs.
Serperate them (shift + left click)
Choose 1 and put the 199 on your bank.
Then tell that you are done with the quest and get the reward.
You lose the 1 ghost bug egg you got with you and get the full reward.
Then get the 199 from bank and get another egg.
Do the same like the time before.
Means you need 202 eggs total instead of 600.
There are more quests with items you should try it on.
Good luck with it.
pekeltje