We're trying to explain to DD2 (18mths) at the moment about the oven being hot, i think it's all about repetition and explaining that hot things can hurt him and they are not to be touched.
DD2 now goes to the oven and says HOT HOT but she still tries to touch it
Could you buy like a fire grate to put around it when it's on? A friend bought an old wooden playpen and took one of the sides off and used that.