It is true that "Mr Muscle" oven cleaner will remove enamel paint without affecting celulose, that's how van signwriting is removed. BUT, do try a very small area of the aircraft first to see if the paint below really is oven cleaner proof because if it isn't, you will damage the paint, fabric and even the wood beneath. Oven cleaner is essentially caustic soda! If the aircraft paint isn't affected, spray on the "Mr Muscle" leave for a couple of minutes and then wash off with a stiff brush. Repeat as necessary. Don't leave the oven cleaner to dry. Keep the oven cleaner away from metal parts especially aluminium even in it's diluted form.