I would remove each pin and meticulously clean the pin and the bore that the pin resides in, and then reinstall the pins and grease them with the new grease. Be careful to wipe any excess from the tractor with a clean soft cotton cloth so you don't scratch the finish. For the cleaning solution, I would suggest that you use a mild cleaner such as Dawn dishwashing liquid and warm water, so it also doesn't harm the fine finish that Kubota puts on every tractor that they manufacture. I would also suggest that you use Meguires paste wax to keep that high luster on the finish. These details will ensure that when you are ready to upgrade or sell your tractor it will bring a premium return on your investment dollars.