Storing saucers is no problem: They nest neatly. The teacups, on the other hand, always threaten to topple over. Here's how Martha handles them: placed cup over saucer, in tidy stacks of no more than three or four that suit them to a T (or a teacup).
See the "Leftover Paint Storage" in our gallery. Transfer leftover paint from large cans to small airtight resealable tubs. Make sure to affix a label to the container; note the color and the room where the paint was used.