[vintagerookies51]

Recently acquired this T206, and I wanted to learn from some experts out there. The back is a Sweet Cap, but there are clearly remnants of what appears to be part of an Old Mill back. I'm sure this isn't very rare as it would have gone for more, but I was just curious what causes this? And is there any extra collectability from this or do collectors look at it more as back damage? Either way I thought it was cool so I went for it. Thanks!

Added: Looked at various Old Mill backs more closely and it seems to be from a black SL back, as the SL backs have "Baseball Series- Selection from..." written. Wish it was a brown