Rebbi Meir maintains that a shard capable of holding a Reviis is a not regarded as an object of significance. But haven’t we learned in the Mishna (76b) that a Reviis in indeed regarded as a significant amount for Shabbos?
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We can do many things with different items, but unless it is meant for that usage it is not Chasuv because of it. This is the idea behind Achila Al Yedai Hadchak. It is possible, but it also has to be meant for it.