Using cheap grungy old brushes to get interesting lines

I love hunting down new art tools that can give me interesting lines. And I've paid a lot for some of them. However, some of these tools can be found at home or very cheaply as Matt Celf on Youtube reminded me. He uses a brush that he doesn't wash. So I used an old stiff cheap brush too, dipped it in indian ink, and this is what I got. I painted the colours with watercolours on watercolour paper. Yep, cheap old malfunctioning brushes can be amazing!