Basically they're acne. I just have to share this because I have been searching all over the net for any information about this with no luck. There are lots of references to black skin disease, also known as alopecia x. I googled pictures of dogs with alopecia x and that definitely isn't what my dog has.
So if your dog has gooey brown or black spots on his belly, ranging in size from pin prick to pencil erasure, and you can 'express' them like a pimple, and they stink,
and they don't itch, they are most likely pimples with a little bacteria thrown in for good measure.
I took the dog to see the vet today for another reason, had her check these weird spots on his tummy, and she even did a scraping and checked under a microscope. It's gunk/oils from sebaceous glands. They're harmless, but if you want to express them before you give your dog a bath it couldn't hurt.
I'm glad to finally know what they are, hope this helps someone else. 
So if your dog has gooey brown or black spots on his belly, ranging in size from pin prick to pencil erasure, and you can 'express' them like a pimple, and they stink,
and they don't itch, they are most likely pimples with a little bacteria thrown in for good measure.I took the dog to see the vet today for another reason, had her check these weird spots on his tummy, and she even did a scraping and checked under a microscope. It's gunk/oils from sebaceous glands. They're harmless, but if you want to express them before you give your dog a bath it couldn't hurt.
I'm glad to finally know what they are, hope this helps someone else. 






