If you have many keys on your key ring, some of them probably look the same and you have some trouble identifying them. Here’s a small tip to make life easier.
You may tried adhesive tape or some threads, but they don’t look good enough. The best solution is to get some of cable number marker tags. They come in a variety of shape and colours, but all have the inner diameter just enough to hold a key center, both flat and cylindrical. Apply a drop of superglue if you want to secure it even more. The tags can also be attached to the whole keying. Moreover, if you attach the same number and colour tag to the lock itself, you’ll instantly know what key is needed to open it.
You may also use size numbers that come on clothes hangers.