I bought an old 1972 Aga 18 months ago, had it installed, and have spent the last 12 months trying to clean at least 20 years of burnt on fat off it, with what must of been nearly every make of de-greaser known to man, I was at breaking point when some gentleman farmer told me his cleaner uses "Astonish" on his Aga.
Hey presto what a simple to use, most effective de-greaser and shiner upper on just about everything inside and outside the house, and best of all it take the hard out of work.
BUY it you WON'T be disapointed.