You do not have to use any particular type or brand of block for mounting my clear stamps, any block will work. My stamps are self sticking with no adhesive needed, ever! They will stick to any smooth surface and if they ever get dirty and lose this self-sticking ability a quick wash with soap and water will bring it back to its original sticky properties.
In general blocks are made from clear plastic (often called acrylic - you may know it as Plexiglas), usually ½ inch thick to provide a good grip while offering some flexibility.
If you are the do it yourself type of person, search out your local glass or sign shop and ask if they have some small “scraps” left over from another project. You may get a lifetimes supply for free. You may need to cut them to size yourself, which can be done with a special plastic blade in your jig saw. When I first started with the clear blocks, they were not readably available commercially and I had to invest in the equipment to cut my own. Hand sawing was only fun for a few minutes, so I went whole hog and bought a chop saw with plastic cutting blade. I still cut odd-ball custom blocks for some orders and flame the edges to give them that polished look . I enjoy my “power tool and fire” time. I may make a video of this since it is kind of cool.
If you aren’t a do it yourself type, I would be happy to supply you with blocks. My stock size blocks are made in America and are laser cut so the edges have a nice polished look and feel.
Care and Cleaning
Acrylic is tough, but it scratches easily - this won't affect it's usefulness.
Wash with mild dish or hand soap, using plenty of warm water. Then pat dry with a soft cloth or paper towel.
Do Not use window cleaning sprays, alcohol or solvent based stamp cleaners (you can tell by the harsh smell). The solvent may make the block develop cracks all over its surface.
If you are stuck in a pinch or need to economize you can substitute any smooth clear item as a stamp block. For instance an acrylic picture stand from the dollar store, and empty cd case, even the lid off a stamp pad will work.