I soak the pan in Dawn and use a green scrubbie... You could try spraying it down with oven cleaner... I have found that to work on pyrex....

I always line my Pyrex now with foil.

I second the oven cleaner suggestion.

Are you talking plain old clear glass Pyrex baking dishes?

I just use an SOS pad. Little bit of water, some Dawn and elbow grease...

Thank you Smom40,Aliceinsocal, and Jazzie.

I have been thinking of using oven cleaner.
And I have some steel-wool.
The steel wool ,in the softest/finest form, can be used to clean glass..

Try Dawn Power Dissolver. I use it on my gas barbecue and have used it on Pyrex.

I would try the smooth top range cleaner. But have always cleaned my Pyrex or Corning Ware with a paste of baking soda soon after using them.

I just stick them all in the sink or a big container and spray with oven cleaner and let it sit as directed on the can. Most of the dirt washes off after this, and anything remaining can be scrubbed with a plastic scouring pad and cream cleaner, or in bad cases treated again with more oven cleaner.

However, with the low price of some of these items now, when something is really old and just won't clean up after multiple tries, it's not really a big deal if you give up and buy a new one. Good oven cleaner (the stuff that works) costs about £2, and most of the glass dishes I have can be replaced for about £2-5 anyway, so in extreme cases it can be cheaper to just buy a new one rather than endless cans of oven cleaner and spend all that time trying to clean them.

dollar store oven cleaner,set for a few minutes,and a tooth brush.....it's clean again

Baking soda has always worked for me when dealing with stuck on food and grease.

But are you talking about real grease or cooking spray splatters? Cooking spray splatters are much harder to get off! I've had some luck using orange cleaner to get it off, but it takes a lot of elbow grease.

I use baking soda to clean my oven and it works easier than any oven cleaner I've ever tried. If something is stuck on so badly that it needs nasty chemicals to come off, I'd probably just call it "stained" and use it like it is!

Thanks again for the great response - I'll try some oven cleaner along with some tolerance and acceptance - which the wife uses..
I'll bet that the splatter is cooking spray..

My Corningware came with a bottle of "official" Corningware cleaner, but it's really just Soft Scrub - so you might try that on the Pyrex.

Soaking and Cheap "artificial" steel wool from the $1 store.

repeating an earlier hint - it is SO worth it........Try Dawn Power Dissolver