What is the yellow stuff on the decking?
Similar to the dirty boards, when Ipe is milled they will have a layer of fine yellow powder or dust. This is normal with Ipe and you should expect it. The stacking sticks marks may be pronounced. Cleaning or a strong rain will remove this yellow dust. This yellow dust is reputed that it may cause dermatitis in some individuals that have skin sensitivities and/or cause allergic reactions in those who breathe it in.