Creating grunge brushes - Créer un Brush Grunge pour Photoshop

My recent tutorial about creating pattern backgrounds sparked some questions from readers if I could do the same for something that is referred to as “grunge”. The pattern tool is ok for repeating items but the grunge look gets it effectiveness just from the randomness I think. So I think it would be better if I show you how to make a grunge brush instead. I know several of those are available for download but there is nothing more rewarding then creating your own :)