275 for an hour. It must be properly vented.
There isn't exactly any way to tell if it is "done" or not. In fact, you soon probably won't bother to put it into the oven. Its something we do when we first start, because we want to be as save as possible, but then we realize that the oven doesn't really seem to make a difference.
If you have heavy metals in your gear or whatever, then the oven isn't going to change that, unfortunately.
Don't get me wrong. Put it in the oven for one consecutive hour; doing two 1/2 hours doesn't count.