You can find it in rsbots.net and powerbot.org i think.
well it was about the receiving account buying (4) potions.
Eg. (4) pots cost 60gp
then the receiving account would teleport to Nardah , and decant the potions into (2). The loophole here is that the (2) potion was 30gp, which meant that they did not count the value of the vial in.
The, then receiving acc would trade the giving acc and the money xferred would be the cost of vials.
so if you bought 100K potions, you would transfer 1.5mil in ONE trade!