So I Emailed Rick Snow...

Thanks Ozland....I know PVC when in contact with heat and humidity(water), degrades and emits/becomes Hydrochloric acid.

What makes you think the coin came into contact with sulphuric acid? Again, wouldn't this disrupt the original surface of the coin, I mean, much worse in appearance than this?

i posted a 1919 woodgrained cent in the modern error forum , kinda looks like yours.
the copper areas look like a dull brass..

I think the 1899 is a case of an improper alloy mix and that area has an unusually high zinc content that results in a big difference in the way the metal tones.

I doubt the white is the result of copper sulfate. If you drive off the water copper sulfate does turn white, but since the water is trapped within the copper sulfate molecules as they are formed it takes several hundred degrees for an extended period to bake the water out of it. Also when it is exposed to water again it will take it back up again and once again turn blue. Copper sulfate is also water soluble so you could wash it off with distilled water.

I have a 1905 IHC that has nearly an identical mark as your 1899. Look goldish colored.

Well, I met Rick Snow (nice guy!) and showed him both coins. He seemed stumped on both and looked at both for quite some time. The 1906 he said was possibly some kind of plating but he did not know what. He rubbed the edge with his thumb and nothing came off. I asked him about the copper sulfate sulphuric acid thing, and he laughed.
The 1899 he said looks like extra metal (he did not know what kind) was possibly rolled into the planchet stock.

You have some interesting explanations for the whitish deposits on the two IHCs. Some of you guys seem to know quite a bit about chemistry. Maybe I should take a chemistry class and brush up on my periodic table of elements and chemical equations!