The following is an excerpt from the book Health Horses by E. Hammes:
Natural healing practitioner and horsewoman

Leather gear and equipment maintenance:

Ropes, halters, saddle girths, and cleaning equipment are to be soaked overnight in a EM. On the following day: brush briefly, rinse and hang to air dry.

Spray saddle cloths on the body side EM, after each use, and on both sides once a week. Hang up to dry overnight. This treatment means that saddlecloths need less frequent washing.

Treatment of leather

After cleaning dust and dirt from snaffles and saddles, spray with EM, wipe with a clean cloth, and leave it to dry. For the treatment for the leather: mix good dubbin with EM ceramic powder and work it into the leather to provide care and protect the leather from fungal infections.

The saddle and gear storeroom should be sprayed with EM twice a week to prevent fungal spores from doing damage.

Additional advice

Hoof knives should be kept in EM, as the electron excess prevents rusting and keeps the knives sharp.