This is a minor problem but maybe someone has an answer. I have 5 volvos, which means 5 ignition keys and a trunk key on my key chain. I have tried to label which car each goes to with a permanent Sharpie and with a label maker, but both wear off. I might be able to use some of those colored rubber loops on the all metal keys, although the big square volvo head might be too large. But how do I distinguish the black rubber headed keys from one another? Any good ideas from multi-volvo owners?