Here goes a quick way to lower the TA ratio on this achievement. . .
The quickest and easiest way to dispel 50 wards is to travel to DETYRE, (on the map it is the central red area). Your goal is Adessa which is in the South East corner against the coast, (its a big gnome city). Once you are there you will run across a long bridge and by a gnome named Apotyre. Keep running South and on your map you will see a South Central circular part and the bottom doorway of this ring is the entrance to Laboratories. When you enter the first gnome, (named Daedinnear), will give you a quest to dispel the wards on 3 chests up the stairs to the left. The best part is that you can exit and reenter the laboratories and dispel them over and over and he even pays you for each one!