Right now the idea behind the elemental ilvan'eth potions is that they help remove the elemental flare penalty when doing casts of 735 and 925.

So, the use of these potions is very limited and also they can be rather difficult to come by at times due to them requiring the hard to find greater essences.

Perhaps another use for these potions can be had so they see more use.

There are 4 types of these potions:
icy ilvan'eth potion (ice)
earthy ilvan'eth potion (vibe)
fiery ilvan'eth potion (fire or steam)
cloudy ilvan'eth potion (vacuum/void or lightning)

Give these potions a secondary use as well because right now they just kind of sit there and folks don't seem to care about the greater essences. You may have a few people that are just sitting on essences, but they have nothing to do with them. So, give them a reason.

Let the potions be used on normal flaring elemental weapons (ice/vibe/fire/vacuum/steam/lightning) to give temporary GEF to the proper corresponding flare. If your weapon has fire flares, you'd use a fiery ilvan'eth potion. Have vibe flares, use an earthy ilvan'eth potion and so on.

Allow these potions to be used with the RUB verb. Hold the weapon in one hand, the potion in another and RUB POTION on WEAPON.
Each application will give 25 GEFs. For every 10 ranks of MIU known, will give an extra +1 flare. At 200 MIU ranks a person could get 45 total GEFs from 1 application.

I've got a couple of weapon swingers that would make use of this application of these potions. 25 GEFs would last them a couple of hunts before needing to be reapplied.

It's been a while since I used on of these potions so I don't remember if there are 4 or 5 doses. If there are only 4, you get a base of 100 GEF (or 180 if you have 200 MIU ranks). If there are 5 doses, you get a base of 125 GEF (or 225 if you have 200 MIU ranks).