I do 1ml/cup for 10 minutes. I've definitely seen redbugs come off, and early on, treated a redbug infestation successfully (I think, 6 months no bugs) with this ratio. Never seen an AEFW come off. I usually buy small frags at a time, so never mixed a large batch, but you can do the math! I believe the origional thread recommended 1/2mL/cup, but at that dose, did not kill all redbugs. I repeated the dip at the above concentration (1mL/C), and that did it for me. No ill effects to date. Never dipped a smooth skin, so cant comment there.