So, I made some things just messing around with the new skin features, and figured some people might like to use them. They are just the extra portion of the skin on a transparent layer for you to drag into your already existing skin in an image editor (or just use the default skin). If you already know how to use an "advanced" image editor (Photoshop, Gimp, Paint.net, etc.) then good for you, this should be cake. Otherwise, don't ask "where do I put this?". Download a good free image editor (again, Gimp or Paint.net are good), and look up some tutorials. Regular MS Paint can't save with a transparent background anyway, so even copy/pasting in it won't work.
First up, and don't ask me why, tighty whities! (they look a bit weird, since I wanted the eyes to show.)
Next, black glasses.
Then, black sunglasses.
A very nice beard.
And lastly, the red hat from my tutorial.
Again, these are just the extra portion on a transparent layer. Any previously mentioned image editor will let you drag and drop/copy-paste this onto a previous skin, and save with transparency. If you feel extra fancy, you could copy more than one, and combine them.