Iv only really used the block dry ice that I just drop on the floor to break up..but i have tryd to reuse the smaller pieces after a extraction and like u said it dosent seem to work as well...but I don't like to use multiple screens cause i think if you allow it to freeze before u agitate the trichs fall off way faster than the material breaks down, so time of agitation is pretty useful in separating trich from plant matter""... this is with fresh material tho, dosent seem to work as well with dry... but I'm sure multiple screens is better...good idea to use the etho to clean up, I'm gonna have to start doing that