This is some of the best information I've received from a fellow stamper on the difference between acrylic(clear) and regular rubber stamps. I copied and pasted this from www.blockheadstamps.com - they sell both kinds and give this information to help their buyers decide what to get. I know that a lot of clear stamp users store their stamps in CD cases - I wonder if they realize this actually contributes to the hardening process because of the light exposure. I'll take clunky wood and rubber any day!
Clear stamps are great tools, but they are not quite like rubber stamps. Here are some differences and tips for getting the best image and longest life out of your clear stamps.
*It is important that you condition clear stamps before your first use. Some people suggest using a fine grit sand paper but I find that using a standard pink eraser to scuff the surface is the best way to help your clear stamp hold ink. In their new state, clear stamps want to repell ink and you can actually see it pooling into little drops on the surface when you ink them. I've shown an example below to show the difference between an image stamped with a rubber stamp, an image stamped with a new polymer stamp and an image stamped with a polymer stamp that had been conditioned with a pink eraser.
Clear stamps are not designed to last as long as rubber stamps. Rubber stamps can last a life time if taken care of. Polymer stamps tend to either get gooey or harden as time goes on. This problem is exacerbated by sunlight, indoor lighting, oil based products, acetone and bleach.
Store your clear stamps in a light-free container, such as a cardboard shoe box. Even indoor light will discolor and eventually harden your clear stamps. These stamps are made of a light sensitive material because they are developed using a light process.
Using and Cleaning
Solvent based inks, such as StazOn, aren't the best choice to use with polymer stamps. The ink is very hard to clean off without their special cleaner. The StazOn cleaner can damage your polymer stamp. Baby wipes are a great method of cleaning polymer stamps. You can also use mild soap and water or alcohol. There are also cleaners made specifically to be gentle enough for use with polymer stamps.
Because polymer stamps are created using a developing process rather than created by pressing them into a mold, they can't be created with as much detail as rubber stamps. You won't notice much difference with bolder or simple stamps but there can be a considerable difference with highly detailed stamps. If you click on the image above to view it in more detail you'll see a very slight difference in detail on the zig-zag stitch stamp. The X stitch stamp is virtually the same.
We've had to modify some of our images when submitting the artwork to make clear stamps. You can easily see the difference in this high-detail floral stamp (below). The small detail dots in the rubber image couldn't be picked up by the photopolymer process so we had to enlarge all the lines on this stamp, make the stamp bolder and darker than the original.
All of the samples on this page were stamped using dye based Adirondack ink. The difference between a conditioned and unconditioned stamp would not be so obvious with a pigment ink such as VersaColor inks.
*Note: Some rubber stamps also need conditioning when new. Fine grit sand paper seems to work a little better than the pink eraser method for rubber. The stamps most likely to need conditioning when new are shiney and have a release agent left on them that needs to be sanded off.
Personal note from me - I have never conditioned my SU rubber stamps - they are of very high quality and I've never had a problem with them.