An extremely fast way to make back 6m in RuneScape?

I was in clan wars in the safe portal. I accidentally went into the risk portal as I had turned off the warning message. I lost an unholy book, worth 19m (not tradeable), ahrim's top and bottom, whip, dds, helm of neitzinot, 1k death and blood runes, glory, ancient staff and dragon boots. FML? I was also having a great day as I had just finished desert treasure. I would greatly appreciate if someone could tell me how I could make this money back reasonably quick. I normally kill green dragons but I'm hoping for another way that is not as boring and even faster money. Thanks heaps. Btw I am level 98+7 with a total level of 1640. Username is "PvM Fraser".