Step 1. Start to remove ink with a soft dry rag. If you are inking correctly, you should only have a thin layer of ink on the surface of your polymer plates. So start with a soft dry rag to lightly remove the letterpress ink. Normal shop rags, worn t-shirts, or synthetic printing cloths work well for cleaning the plate surface. A hard hand is not necessary here; a light stroke can remove most of the ink.
Step 2. Wipe polymer plates down with a little mild solvent to remove the remaining ink. Choose a mild solvent. Printers who want to keep their photopolymer plates should consider a water-miscible solvent. Aggressive solvents that can clean lead type (like methyl ethyl ketone (MEK) or denatured alcohol) often dry out polymer plates, causing them to crack a few months later. Do not use alcohols. Keep solvents away from plate edges so that the solvent doesn’t contact the film adhesive. We recommend using solvent sparingly. Water-miscible solvents do not mean that you use water for washing your plates. It can soften and deteriorate your plates so they start to chip or crumble.
Step 3. Wipe off your letterpress plates one last time with a dry rag.
On all these steps, remember don’t rub too hard! The photopolymer is difficult to damage through scrubbing, but you should treat it like any typographic surface and not use too much abrasion when cleaning. Because you aren’t putting a lot of ink onto the plate relief surface, you can easily, but firmly wipe off the ink from your plates with just a light hand. Your polymer plates can last for several years if you follow these cleaning instructions (and also store your clean plates properly).
If you’re not planning on saving your plates, just clean them with any normal press wash before recycling them.
Posted in: Using Your Plates