The best place to get dye is in the pyramid secret place....
Which is the last pyramid in Egypt...But u need to finish the quest where u get the Bucket of water to the camel...then u get the key to open the door...inside the pyramid the mummy is level 87 and 88, 1k+ Hp suggest to get a team...Plus only the fire mummy have poison..

Drop:Dye,Oak Wood,Rice Wine,and Cotton Thread...

Hope can help you!... =)