Before you begin, be aware that it is possible to pull the dye out of some leathers as you clean and that water, soap and conditioner will likely change (darken) the color of your bridle, especially if it is new. If the bridle’s manufacturer suggests specific cleaning products you will want to use them to maintain the color and finish of your
Take apart your bridle. Don’t worry. Undoing the hook fastener on the reins and cheek pieces of English bridles can be difficult. Get a purchase on the leather just forward of the little hook and pull it upwards so the end of the strap is pulled free of the keeper. You can now grasp this end and pull forward, taking advantage of the little slot cut above the hole to pull the rest of the strap free of the hook. Free the end of the strap from the second keeper. If the leather is particularly stiff or thick I sometimes ask someone with stronger fingers for help, or I carefully (so as not to damage the leather) insert a small screwdriver underneath the leather just forward of the hook and pry upwards carefully. The little keepers are very thin and the stitching can rip easily, so be careful if you resort to drastic measures.
Put the bit in some water. I don’t like to use a cleaner, as I worry it won’t rinse off completely which would be awful for the horse. I leave it to soak while I disassemble the rest of the bridle. After a few minutes you should be able to wipe off any dirt residue (chewed grass/hay/treats) with a clean cloth. Anything that’s tougher to get off could be scrubbed with a brush, but I just scraped the few thick spots with my fingernail.