Can you use BE for trombone or euphonium?

I think so and I hear it from more and more people. I only play trumpet and flugelhorn, so I cannot tell from my own experience.The basic thought is that BE makes your lips move in more or less the right direction and that goes for all brass instruments. The exercises are written for trumpet, so if you play trombone you will have to adjust some of the exercises, but the basics stay the same.