One common problem in handling polymers, especially those with notably resilient mechanical properties, is cutting them to size for measuring or grinding. Notably there is a lack of laboratory equipment truly suitable for doing this. If doing this by hand here are a few practical tips:
For relatively small cuts, semihard polymers can be done using either clean reinforced shears or clean tin-snips.
Larger cuts of polymers are best done using a clean, resilient knife with a flat blade (Santoku knife or meat cleaver, reduces polymer rolling away) on top of a cutting board. The process is to hold the knife still on top of the polymer and then hit it with a hammer (either regular hammer or better is a rubber/wooden mallet so as to reduce damage to blade). Between hits gently rock blade forwards or back so as to be cutting with a slight angle through the polymer. No matter the case keep in mind the cutting blade will recieve a great deal of wear and tear quickly from this so best not to use your favorite knife or scissors for this process.