Here is a quick “How To” on Uninstalling  extensions or plugins on Google wave, with Screenshots.

1. Click on “Settings” on the Navigation Panel. Or, you can type “with:settie” in the search bar.

Uninstall Wave Extensions

Uninstall Wave Extensions

2. Open the Wave “Extension Settings”

Uninstall Wave Gadgets

Uninstall Wave Gadgets

3. Find the gadget you want to uninstall or remove, and click on “Unintall” or “Remove”

Uinstall Wave Addon

Uinstall Wave Addon

Done !!