I was given a lot of already milled oak, it's 3/4" thick. That's the good news. The bad news is that it was stored outside under a tarp for a couple of years with some of it stickered, and a lot of it turned black or have lots of black areas. I'm guessing it was due to water leakage. If I try to run these through my planer to clean off the black, then they will be less than 3/4". The black does not look like mold. Is the black "tannin" (I think that's the word) that has come out of the wood? Is there a chemical that might take off the black? Randy