Skinned Mayo Cut Plug

[G1911]

Using the big scan here and more detail -

Note the rough texture throughout the back that appears even in the scan. Mayo cards have fairly smooth backs.

Mayo's sets are thick, and some skinned cards are almost as thick as a proper card (the thickness varies very very slightly on N310 Mayo pugilists, I have not had enough N302's to make any conclusion on them but it may be the same). A back layer being peeled off can hard to tell just by thickness. Skinning is paper layers separating, and this usually doesn't create a clean back on a skinned card as the paper will usually betray layering, a rough texture, and unevenness.

On an N302 specifically, a white appearing back will usually be skinned as almost all proper cards had the black stock reverse. Mayo's are also less susceptible to natural skinning than most other 19th century cards, because they are not thin albumen photographs pasted onto a backing like the photographic cards.

One of the benefits of skinned Mayo's is that the backs are blank cardboard anyways, so you aren't really losing much eye appeal as there's nothing to see on the reverse, unlike cards with advertising or stats. Baseballers, footballers, pugilists, military uniforms or actresses the Mayo's look great and have aged better than most of the 19th century stuff.