For the key ring idea, I find that using the edge of a key works well too. If you take the key and push one of its top edges between the two bands in the key ring, it will pop open, with the key sandwiched between the two. Do this near the start of the helix and you can just slide the key on. You could also do this with other fairly hard and sharp edges to prop it open when you're putting on things without a hard and sharp edge. The staple remover idea is more elegant I guess but I can't say I've ever had one available when making additions to a keyring (best do it immediately, I'm quite clumsy). I'm a habitual nail biter too so I haven't any nails to use, let alone save, hence this little trick!