Just got these from my Dad.
The one on the left is a Made Rite nylon bristle (marked with the number 23). I think it was my grand father's? I'd think about re-knotting it, but there's a couple of cracks in the handle. But for a synthetic brush it looks totally usable.
The one on the right is a Century (marked with the number 5) that he says he's sure was my great grand father's. I don't see any cracks or anything in the handle... what are your thoughts on the bristle? Horse, maybe? Doesn't feel like my boar bristle at home. I'd like to get this one re-knotted, but don't know where to even begin. I'll have to search around a bit and see if I can find how to go about it. I'll clean up the handle for sure, it looks like a toothbrush and some light cleanser will do it well. Still smells like whatever soap he used with it (smells great!).