I use EOs in mine. For a 2lb batch I use .75oz of EO and mix it with 1.5oz of mathcing FO. With that small amount, I can still feel the EO tingle on my skin and it anchors the FO real nice. So far I have made the following batches: .75oz lavender EO mixed with 1.5 lavender FO, .75oz Sage EO mixed with 1.5 Lemongrass Sage FO, .75oz Vetiver EO mixed with 1.5 Vetiver FO, .75oz Sandalwood EO mixed with 1.5 Sandalwood FO, They all came out smelling Grrrrrreat!! Next I am thinking of doing .75oz of Lime EO mixed with 1.5oz of Violets and Lime FO