I had my solid deoderant in my quart sized ziploc and was told I didn't need it in there by a TSA agent during airport screening (was having trouble fitting everything in it). On my next trip, I left the deoderant loose in my carry-on and it caused me to get pulled aside for a bag search.
Next trip, if I have room, my solid deoderant is going in my ziploc or I'll put it in a 2nd ziploc and pull it out during screening. Since its not required to be in a ziploc, I won't officially be over my one bag limit but I don't know that every TSA agent will see it that way.
...TSA site has this statement:
Each traveler is limited to ONE, QUART-SIZE, clear plastic, zip-top plastic bag of travel-size toiletries (3 ounces or less). What does it mean by "toiletries"? Elsewhere on the TSA site, it is explained that the reason only one quart-sized bag is allowed is to limit the total liquid volume one person can bring onboard.