Tin of keys

I live in a very old house. Almost every door and cupboard has a lock and key. Unfortunately the two have become separated from each other over the years. I have been trying to tidy up my son's room and make the cupboard doors shut properly. I have another box of keys bigger than this one and I've been through them both. No joy. I taken off the lock and I'm going to replace it with one that was in the box and does have a key. The problem is there is no turning end on the key so I will have to fashion something to give a bit of traction. As I write this I realise it will probably never be done and the cupboard door will be as it was for at least 25 years.