Why do sections tear as they are being cut? FAQ Report The blade/knife edge is blunt or there is dirt, dust, frost or rust on the edge. Remove the cause or replace the blade. The leading edge of the anti-roll plate is damaged. Replace the plate. There are hard particles in the tissue. Use tape transfer technique or select another specimen. The back of the blade back is dirty. Clean, or replace the blade. The temperature is too low for the tissue to be cut: increase (raise) the temperature by 5 °C, wait for a few minutes and try sectioning.