It may sound strange, but I have had better results with a Burma Shave natural bristle (and ugly plastic handle) than with a Caswell-Massey badger (sold as "pure" but actually "silver tip") brush. I am talking about hard soap.

I bought the Burma shave the other day from Albertson's for 4.99, just to give it a go. After some testing, I think the only thing preventing me from using it all the time is its ugliness. And a new silver tip I am expecting in the mail... I hope it turns out alright