Depending on what is left on the plates / in the pots, I use paper towels or a rubber spatula to wipe off into the trash can. I also use a rubber tub for washing of pots, dishes, utensils.
In most cases, unless the water is relatively clear, I empty the tub into the black tank.
Legal or not, please be responsible and don't dump your mess on to the ground. It attracts unwanted insects and critters. Imagine if all RVers did that.
In terms of going all paper and plastic all the time: i use paper plates for certain hard to clean entres, but that's it. Our landfills will love you but many of us... not so much.
