hi ann,
the "castille" i make i leave unsented (80% olive), and those that have tried it remark on how they like the slightly sweet olive smell.....but if you want to cover it choose a strong EO like peppermint, that will cover it (i generally add 1 tbs per pound of soap.... but you can alter that depending on how strong each EO is.... i like 2tbs of peppermint eo in a 3lb batch for example). hth