Put the rosemary sprigs into a large microwave safe bowl and fill it about 3/4 full of water. Microwave on high for 3 to 4 minutes, or until the water is very hot.
Remove the bowl from the oven and add the washcloths. Let them soak for a few minutes. Carefully (they will be hot!) remove them from the water and wring them out. Fold the washcloths in half, place 1 rosemary sprig on each cloth, and roll them up like a cigar. Put them onto a microwave safe plate and heat them on low for 1 minute. Give them to your guests when they sit down at the table.