I would just hang on to them. You never know when you'll break or lose a needle. And it usually happens when the stores are closed. I'm assuming you already have pairs of the same size as the mate-less ones.
Funny that you mention a feminine napkin. I once won a contest in Bicycling Magazine for the oddest thing in your pack with that. I used to keep one in my cycle pack and one in my hiking pack for the same reason. An EMT once told me 'field bandages' are made of the same absorbant material.
You are way ahead of me! I'm making Dumpling bags and fingerless gloves too. I love that Dumpling bag, so quick and easy and looks spectacular. I'm also making socks and some scarves for charity. I'm almost done with the scarves because I have to mail them off soon.