Never underestimate the importance of a clean cutting deck. Not to worry, with a little diligence and a simple tool or two, cleaning your mower deck is easy and will keep it in top shape. Other reasons include cutting grass that’s too wet, mowing with dull blades , or cutting long grass with a mower height setting that is too low. Trevor Raab When working on a gas-engine mower, remove the spark plug wire. In the end, these sprays will help but not eliminate the need for a manual cleaning of the cutting deck.