1) The Grillaholics Grill Mat Heavy is safe up to temperatures of 600 degrees (F), and should not exceed this temperature, or come into direct contact with flames. Both can cause damage to the mat.
2) If cooking particularly fatty foods (like bacon), you may run into the problem of a large amount of grease pooling on the mat. For tips with dealing with this, read this article.
3) Always use silicone or plastic tools when cooking on the Grillaholics Grill Mat. Metal tools can scratch the surface of the mat and cause damage.
4) The Grillaholics Grill Mat is completely dishwasher safe, but if you'd prefer to wash by hand, simply rinse under warm soapy water, and (if necessary) scrub gently with a soft surface like a sponge or paper towel. Never scrub with something that could scratch and damage the mat (like steel wool).