Leader wallet(s). I cut pieces of index cards to write down the configuration of each leader.
A few times a year, I'll go through them and repair any that need it. I really like the old Cortland wallets that have vinyl sleeves, rather than ziplock baggies, but they're getting tough to find these days. The vinyl wallets held like 10 leaders, were easy to use, and very durable.
Durable 7mm clear PVC waterproof zip bags
Quick attachment swivel clip
Stainless steel grommets for quick drainage of main compartment
Accordion style design for easy expansion and viewing
Heavy duty rip stop material
Industrial strength Velcro closure on main flap
Size : W 7" x H 5 1/2"
I thought you were asking what to do with the leader after you take it off. What I did was hook one end in a slit of the foam spool and wrap the rest of the leader on the spool and put the other end in another slit. Then I kept the spools in 3x5 zip bags which I kept in the zipperd pocket on my pack. Those spools make wrapping and storing leaders ALOT easier.
I have a slight obsession with leaders. I carry a ton of them in my leader wallet. I personally feel that leaders are more important than patterns.( for trout anyhow)
Looks nice, and for $20 or so, it should be. I don't care much for ziplock closures on the sleeves though. Those things never last very long.
This is the kind I have. They last forever, and are only $5. I just coil the leaders up like the store bought ones, and slide them in to the sleeves. Even when full, the wallet is only about 1/2" thick.