I have to tell you a little story. I've always liked Ozium but I became sold on it after an incident with my aunt's car, her poodle and a skunk. Can you guess where this is going? LOL! My aunt had been cleaning the inside of her car and got a phone call. She went into the house leaving the car door open. She was long winded and it became dusk. The skunks came around and her little dog just couldn't seem to learn to leave them alone. Needless to say, the dog got sprayed in the face, jumped into the car and rubbed all over the seats! It just so happened that I was having dinner with her that evening and when I arrived she told me about what had happened. She was almost hysterical. Kept saying she would never be able to drive her car again. I didn't know what I could do to help her but I did have a small container of Ozium in my car. I knew it was good stuff and figured, nothing ventured, nothing gained, so I thoroughly sprayed the driver seat and emptied the canister into the car. (This was the smallest size canister - about the size of your index finger - and was only maybe half full.) I made sure all the windows were closed tight to hold the Ozium in the car. The next morning there was not a hint of skunk odor in the car! At that moment I became sold on this product. I have used it on many, many fabrics and it is totally safe. I have several more stories about how Ozium has saved things but I won't bore you with them here. LOL! I suggested putting the leashes in a bag over night to hold the Ozium in. Does that make sense? Kind of like making sure the windows were closed in the car. I wouldn't store the leashes in the bag. You probably don't even need to do it over night...maybe just for an hour or so. I just said over night as that is when they will not be in use. Give it a try for the anal gland odor. I think you will be pleasantly surprised. I use this in my house all the time. It only takes a tiny squirt to clean the air in an entire room. Let me know how it goes.