Yes, I use it dry. I have only ever used Borax on dry fur, never wet. Tomcat is the resident expert on using Borax and he was the member that I learned about Borax from in one of his posts on this forum. Getting close to the last receiving date one year, rather than burn the midnight candle and scrambling around trying to dry wet, washed pelts, I decided to try the Borax thingy. It worked like a charm and now I'm a big fan of it.
If you do a search you can find before and after Borax pictures that both Tomcat and I posted on this forum. I have a red belly coming off the board today that I want to use Borax on. I'll try to remember to take before and after pictures and post them up.