Did the proposed preparation entail heating? Might have described a process that destroyed most of the mescaline to spare you the experience, which can be quite frightening and/or debilitating.
I've never come across someone that does more preparation than drying, so to me it seems suspicious to suggest anything else. Mescaline is water soluble so one can make infusions, but it takes a fair bit of plant material to get dosed so there isn't much practical use in doing so.
Reducing bitterness likely reduces potency as well. Mescaline itself is quite bitter and whatever solvent is used to flush out other less tasty substances will likely solve mescaline as well.
Drying slightly improves the taste but not by much.
I've never come across someone that does more preparation than drying, so to me it seems suspicious to suggest anything else. Mescaline is water soluble so one can make infusions, but it takes a fair bit of plant material to get dosed so there isn't much practical use in doing so.