You take the wife's best big sharpest kitchen knife and place the sharp edge on which side of the gasket you like . Then you use the hammer to tap -tap - tap the back edge of the blade . If necessary work around .
try this
Using a sprinkler about 3/ 4 inch tall , so the blades don't contact it , put it under the deck and at full throttle run the blades for a minute or two then move the tractor so another area is cleaned etc.etc. With a little skill ya won't get wet . I find that easier than connecting...