Looking for soap without soap scum

So I've noticed that my razors tend to build up soap scum after using my Proraso soap. I'm wondering if anyone else is aware of any artisan soaps that don't leave this behind. I suppose its not an enormous problem but I'm not that picky about soaps/scents as long as they later well and it gets a little annoying having to clean my razors (especially adjustables and butterfly doors) every few shaves.