For my peaches and nectarines, I cut up into marble sizes and then with my food vaccumn I cut extra long plastic bags and then take all the air out and seal. When I thawed, I used a wooden rolling pin and my hands and crushed well. I poured it into my course straining bag and then crushed more with my sanitized hands.
With my Zante Currants, I froze sticks, stems, leaves, everything. Once frozen, I then went through and then de-stemmed, leaved and such, then quickly air sealed again, for later crushing. The grapes were very easy to clean while frozen especially since they were very small. I didnt want to crush them too soon.