beat me to it, rinse with bleach water,, save the slow cooking for beef ribs.When baking gravel, add some seasoning. Plain gravel has little taste. LOL!
Why don't you just spread it out on a tarp and let it dry out....preferrably in the sun. Why risk peeling the paint, stinking up the house, and wasting energy using the oven. I still would go the bleach method since it was used/wetIt wasn't new it was wet and I needed it to dry faster than it would have just sitting out. I Wasn't trying to clean it I just didn't want to ruin the gravel