How to reduce web platform game size

Greetings .
I have created my 1st game successfully and now i want to upload my game on http://www.y8.com/
and
http://www.kongregate.com/
sites but they have only 20mb of limit and my game file size is 86.6 (just 8 straight forward levels and , x=1,y=1 level textures 1mb of size , some models less then 500kb) . But my game size is still large .
Please tell me how can i reduce it less then 20mb .

There is an article in Unity Manual over this: Reducing the File Size of the Build.