Every now and then a sippie cup will be left out overnight on the table, or a cup of milk will make it's way under the car seat or the couch. When we find it, we say "don't drink that, it's old milk."
TJ found out once the hard way.
I gave Julia some juice in a Pooh Bear juice container this morning. We went out for some fresh air for about 30 minutes. I told her to drink the juice. She wasn't having it.
"That's old juice!" she tells me. "NO OLD JUICE!!!!"