1 - Go in the queensdale jumping puzzle cave (south-east corner of the map)
2 - Follow the path on the screenshot :
3 - Loot the bag :
4 - log out / log in and if you are on overflow server there is a new bag.
5 - easy to script with autoit for example.
There isnt always copper and jute in the bag sometimes only tools.
The overflow exploit have been nerfed for chest but not for this little bag.