Here's how it played out:
I pulled the beets and hosed them off. Then I scrubbed them with a soft vegetable brush. Chopped off the leaves, but left a couple inches of stems. Two different sources told me that would keep them from bleeding out like before.
Then I set them in a casserole dish, covered them tightly with foil and baked them. At 350 degrees, they were in there for way too long. I got busy and didn't check them for over an hour. I was cooking some chicken too, and for some reason chicken takes a long time for me. So they were both in there for over an hour.