Suggest, level the deck on concrete or asphalt - it should be fine in grass then. The most important part of level clean cutting grass is keeping the deck clean. When finished mowing, wash the bottom of the deck clean. I don't know about your rig, but sometimes I have to stop and wash my mower deck clean to get clean - even cutting. I use a pressure washer about every other time and after each mowing I use high volume - 50 psi water from the well to clean the deck. I keep it squicky clean. 

I have heard about the big gravel truck pour on or spray on liner system, but I would guess sand, dirt and mud would still imbed into the hard plastic and build up / stick. I have a rear discharge mower deck, so clumping happens more then on a side discharge system. I hate the looks of clumpy lawns . . .

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