How NOT to stack second hand or used glass blocks...

Here is a perfect example of how not to stack glass blocks if you wish to keep them free from scratches.

You can spend all the time in the world on cleaning them, chipping off old mortar, repainting the sides again where the paint pulled off with the mortar and then stack them flat down on the faces that are seen when installed and if you have the tiniest particles of sand, grit, old mortar crumbs or stones and you are almost guaranteed to scratch the faces of most of the glass bricks you just spent hours salvaging. It only takes the tiniest rubbing movement to damage

What an unnecessary waste of time and energy!

Please stack them upright and leave a gap between each glass block so that they don't rub together and you should be able to use them again and be happy with how they look.

This photo is fairly typical of what you will see of glass bricks at demolition and salvage yards.

Glass blocks stacked face down like in this photo will inevitably lead to scratches on the finished glass surface.