You will need at least 30 paint brushes. Then go to the Arcane University.

You can go over the gate as what i did (there are a lot of ingredients there that are special too) or go on top of the line of building.

Then go down it and jump off the castle. Now you're outside, but it is all blue and floating grass. To get out of the glich 1) teleport out or 2) use the paint brush cheat as a back up.

Warning: If you go inside for ingrediaets then you need to paint brush cheat back out.