Volcanic ash

The Volcanic ash is a members-only Old School RuneScape item — “One of the ingredients for making ultra compost.”. Its Grand Exchange buy limit is 13,000 per 4 hours. Right now it buys at 76 gp and sells at 89 gp — a net margin of 12 gp (15.8% ROI) after the 2% Grand Exchange tax of 1 gp. High alchemy yields 120 gp.

To flip it, place a buy offer near 76 gp and a sell offer near 89 gp; the spread minus GE tax is your profit. Confidence figures are model estimates from live OSRS Wiki prices, not guarantees — flip responsibly.