There are NPCs who can decant potions either to make 1, 2, or 3 dose into 4-dose potions. Or to convert 4-dose back into 3-dose. There is also an NPC who can combine enchanted jewellery to consolidate the charges.
Bob Barter is one of the Market Price Guides located in the northwest corner of the Grand Exchange. With the update of 9 September 2008, players can now talk to him and he will combine any 3-dose, 2-dose and 1-dose potions in your inventory into vials containing 4 doses. He will also combine barbarian potions and calquat kegs.
Teplin Macagan is a Dwarven NPC located in Oo'glog. He can decant players' vials into flasks and vice versa even if noted. He can also convert 1-6 dose flasks into 1-4 dose vials. He is located by the town's bank. You must have completed the quest As a First Resort... to be able to decant potion flasks.
Zahur is a woman in Nardah who will decant 4-dose potions into 3-dose potions, for a small fee. The fee depends on how many vials are needed. She charges 2 coins for every normal vial and 15 coins for every juju vial she supplies. The player does not have to supply empty vials for the decanting, as Zahur's fee covers this service. Indeed, Zahur will use a player's vials if a player brings some. If you bring your own vials, the price goes down for however many you bring. Ex: You bring 4 super attack potions to convert into 1-dose. 12 extra vials are needed to complete this. If you bring 4 vials, the price will be 16 gold coins.
If you bring noted 4-dose potions then these are converted to noted 3-dose potions, thus you can convert as many as you need in one go.
If you bring smaller doses, such as one dose potions, she can decant them upwards into their two; or three dose equivalents. This is much like Bob Barter.
Zahur is located in the Southern most house in Nardah. Take Ali's carpet from the Shantay Pass to South Pollnivneach, the another carpet on to Nardah. Run South till you get to Zahur's house, which is just East of the bank and is marked on the mini-map with a green star.
Combining Enchanted JewelleryEdit
After the update on 20 October 2009, Murky Matt can combine players' enchanted jewellery charges, for a more efficient use, much like decanting. Two games necklaces with 1 charge each can be converted into one games necklace with 2 charges, for example.
After the update on 15 December 2009, Murky Matt now combines ferocious ring charges.