Do it bullet nose jig mold
It's the best place to farm Frostweave Cloth, but only for level 40+ players. If you don't have a high level character, scroll down to the bottom of the guide to find alternative farming places. Here is a step by step guide how to farm there: Step 1. Go to Naxxramas in Northrend and set the raid difficulty to 25 before you go in. You can do this by right clicking over your own portrait.