I use avocado oil for mayonnaise.
I have been wary of trying refined coconut oil because “refined” often means treated in some unspeakable way. Costco now carries Nutiva Refined Coconut oil in a humongous tub, but I’ve been resisting for that reason (and I don’t mind the coconut taste, actually enjoy it). But I just googled it, and according to Nutiva’s website:
Nutiva Organic Refined Coconut Oil is made from dried coconut meat, or copra. Unlike other companies that use harsh chemicals to produce refined coconut oil, we gently steam refine our oil to achieve a neutral-flavor. Because of our commitment to producing the highest quality products, this process is certified organic and uses absolutely no chemicals.
So maybe I’ll try it after all!