Great find and welcome to the club. First off, been there done that. Without pics I'll give you my hit list.
Supplies: All found at the Grocery store
LARGE garbage bags
EZ Off oven cleaner (2) cans
Heavy bristle brush
Softer nylon bristle brush
Bucket of hot soapy water
Garden hose for rinse water
several roles of paper towels
1.) Completely disassemble everything. every nut bolt and screw. Take photos if need be.
2.) Spray down the grates with EZ off and put them in a sealed black garbage bag and set them in the hot sun for several hours
3.) Spray down the inside of the lid, not outside, inside and bag it in the sun
4.) Spray down the bowl and set it in the sun
5.) while you wait clean up all the other parts with a magic eraser and 409. You WILL need a new wiper blade assembly, order from Weber, or get one form the hardware store. You can waste your time trying to reshape them, and then will go buy new ones.
6.) Take out the grates and scrub them with the brushes until they shine. repeat steps as needed
7.) take the top lid and the softer bristle brush and scub a dub dub. Rinse and repeat.
8.) Use 409 and magic eraser on the outside of the grill, lid and bowl. he magic eraser will remove black spots without scratching the surface
9.) See step seven for the bowl
When all is sparkly clean rinse well, dry with paper towels and put it all back together, refer to photos you took. Now take pictures to post here and show your quality work. Now get yourself back to grocery store. Buy some food and get it dirty.
2000 Weber Simpsons OTG
2010 22.5 WSM
Smokin' Bucky UDS
Early 70's Red Weber Statesman
1995 Red Weber Master Touch
2010 Brick Red Touch n' Go Performer