Best Cleanser for CEFIONTECT?

I have a newly installed Gwyneth one-piece which I already love. The instructions that came with it said to clean it with a brush and "neutral detergent" (whatever that is) and warned against using what I think are the usual bowl cleaning products. Can anyone tell me what they think the best cleaner is? Thanks.

The only thing they discouraged is a cleaner with an abrasive.
Nothing that will scratch the bowl.