Chosen Solution
I can see one on the battery and one is visible once the battery is removed. Where else ? What about the white bit around the trackball ? Thanks!
As near as I can tell, there aren’t any more. See: Nexus One Teardown
I saw one little circular white spot at the charging hole at the bottom of the device. Maybe that it’s?
There is a rectangular water detection sticker on the battery, next to the connection points. There is another one on the phone placed right under the battery connection prongs.