Ha ha ha!
It's when you take the old one outside to be dumped that you realise that all those little shadows aren't shadows, but bits you've missed when cleaning the thing!
A few years ago, our old oven caught fire in the grill, for the usual reason of hot fat spitting upwards! I cleaned it away as soon as I could and forgot about it all until we replaced the whole thing a few years later! Turning it on its side to carry out to the tip showed up a huge melted burnt area and a really nasty looking state of affairs, but I'd missed all that!
The upside of today however, is that the new cooker is now in place, and as Sainsbury's (Argos) in Staplehurst is the only place locally where you can buy my fave lager - Pils, it hasn't been such a bad day!