There are lots of brushes out there, but I started using this wooden handle one 10 years ago and it just worked really well for me. This contains HOG bristles that are stronger despite vigorous agitation.
TIP: I have 2 brushes for the interior, 1 long or standard length, and another that I cut with scissors about half the length to increase the stiffness and cleaning aggressiveness. I use that a lot on steering wheel stitching. Be sure to remove the metal “tie” around the bristles. This is done to protect the hog hair during shipping.
Tough hogs hair bristles
Comfortable wooden handle
Excellent for cleaning leather, plastic, upholstery, fabric, & buttons