Anyway here's the first, taken off from The Singapore Women's Weekly - Feb 2004, Reader Hints page.
To clean your oven rack, wrap it with foil - dull side out. Heat it on high for 10 to 12 minutes. when it's cool, remove the foil. All the burnt grease and food will fall out, and the rack will be spotless!
Contributed by Glarista Grant, Bedok North Avenue 2