السلام عليكم ورحمة الله وبركاته Ustadh, can one eat in a pizzeria where pizzas with pork on it is selled. I am not eating it, but my pizza (with cheese,..) is in the same oven. And if one accidentally cooked a pork pizza in his own oven, does one have to clean it before baking again?

Ustadh AbdulAziz al-Haqqan

You must clean the oven without a doubt, therefore no unless the oven and everything they use is purified from pork or alcohol etc.