Grills

My oven it starts up fine heats up too the point where the grills are red hot then after it shuts off for a certain interval of time since all ovens do that and then rather then turning on again soon it takes about 15mins for it too start re heating…
Is there anyway too fix [...]

I have a Grill Mate 50,000 BTU Barbecue with Reversible porcelain coated cast iron cooking grills with a Porcelain coated warming rack, how do I clean it ? I bought it in July, and im putting it away in the shed for the winter, how do I clean it ?
best way is to run it [...]