Witch's Potion

Getting Started

 * Talk to Hetty in Rimmington.

Finding the Ingredients

 * Eye of Newts are a common drop from Level 24 Cave Crawlers. They are located in the Low Level Dungeon of the Slayer dungeon (Dungeon teleports > Slayer Dungeon > Low Level Dung).
 * Once you have an Eye of Newt use your Game's Necklace and teleport to Edgeville dungeon.
 * The Giant rats are right in front of you. Kill them for a Rat's tail.
 * Now you need to farm an Onion. Farming will require a spade, seed dibber, rake and 3x Onion seeds.
 * While you wait for an Onion to grow you can go harpoon a shark and purposely burn it. Sharks can be harpooned in Catherby (Skill Teleports > Catherby).
 * All of the ingredients needed above are easier to get yourself, but are available from other players

Finishing the Quest

 * Return to Hetty in Rimmington with all four ingredients.
 * Once you finish speaking with her you are finished with the quest!

Rewards

 * A Yellow Cape
 * 90,000 Magic experience
 * 50,000 Gold Coins

Transcript
Click here for a transcript of possible conversations encountered throughout the quest.