Imaging Earthshine on the dark side of the Moon, particularly without blowing out the illuminated limb, is a challenge. There are a number of competing factors. You'd like the sky as dim as possible, meaning farther from the new Moon, but you want as much reflected Earthshine illuminating the dark side as possible, meaning closer to the new Moon. Somewhere in there is the perfect phase that will allow you to maximize the reflected Earthshine but minimize the scattered sunshine in the atmosphere, which for these purposes just raises the noise floor and obliterates details.
Yesterday was the new Moon. Today at sunset the Moon will be 3.5% illuminated at an altitude of 15 degrees above the horizon and have roughly 1.5 hours before Moonset. Tomorrow at sunset the Moon will be 8.5% illuminated at 25.5 degrees above the horizon and have more than 2.5 hours before sunset. The next day, 15.1%, 35 degrees, 3.5 hours. The next, 23%, 43.5 degrees, 4.5 hours. The Earth's phase as seen from the Moon is the opposite of the Moon's phase as seen from the Earth; so as the Moon's illumination is increasing, the available Earthshine is falling, 96.5%, 91.5%, 84.9%, 77%.
Somewhere in there is the perfect time to image Earthshine. The exact calculation is beyond the time that I have to put into it at the moment. It would depend on the Earth's illuminated fraction as seen from the Moon, the Moon's albedo and distance, as well as the sky flux of scattered sunlight at the Moon's current altitude as a function of time as the Sun sinks lower behind the horizon, as well as any city light domes in the direction of the sunset/Moonset.
But that perfect time is in there somewhere. My challenge to you lunar imagers is to try to go find it. For myself, I may not get it. Trees. I might get a shot between the trees given that it's winter. Tonight the Moon may just be too low. Tomorrow, too cloudy. I suspect the day after will be too late. But I bet somebody can get the shot and post it here.