I had remarkable success cleaning just using Halfords Foam upholstery cleaner and a towell, then finishing with a "bobble off" shaver on both my drivers seat and steering wheel. If I could figure out how to post pics show a before and after
I don't think you need to be too scared of Alcantara, in my experience its not that fussy about being cleaned but you I know that you CAN end up staining it with some products or by getting it very wet with them.
Cheers
Mark