I think he is talking about the new SLOT ID, I don't have it yet but you're meant to create a slot and install the code on your site, so when you want to change a size or link color you simply change it in your adsense admin and it reflects whereever you've installed the code. But I don't know how to delete them because I don't have them yet.
I've wrote it as clearly as possible, when you've made an Ad template for a site and realize something is wrong or no longer need it, how do you get rid of it?
I'm using Finnish AdSense, but I'm trying to explain anyway. 1. Go to AdSense-settings (second tab) 2. Select the third subtab (color palette or template etc.) 3. Scroll down, there's a remove button link on the right next to saved palettes list.