If you have a number of units created, then chances are you have some missing products in there, those products which have gone out of stock, or been discontinued. Whilst you have options for dealing with out of stock items, there comes a point when you might just want to flush out the units. Previously, this meant, trawling through each unit, removing products and replacing them with up to date ones, which might suit some.
Others however may prefer to zap them all, in one click of a button. Now you can!

Remember using this tool, may leave you with empty units, so be careful, maybe the missing product page would be more useful for you.
If you want to flush out all the missing products from all of your units, then simply click on the button at the top of the missing products page. This will delete them all, leaving your units with only products in stock.
I will reiterate the best option for clearing out the missing products is via the fix link on the missing product page, where you can delete the products individually, and replace them with alternatives from the fix page. But we were asked for a zap all, so there you have it.