How can you restore the default icons after installing a home replacement like Open Home 6 I have installed Open Home 6 as a home replacement on my Archos 101 apad.

Is there a way to revert to the default icons for gmail / market / contacts and the like ?

Are icon sets a system wide setting ? Or are those sets specific to the software application which displays them.
AFAIK, OpenHome icons are specific to OpenHome. If you switched to another home scren app, the icons would revert to the default icons. If you want to keep OpenHome but not their icons, you would need to replace the icons through OpenHome.