I do not warm it up myself - should be okay as is, I usually recommend that in the winter months with colder room ambient temps or when you pull it out of the mailbox and it's -10 C outside. you can always just put it in your pocket, heat vent, on top of a piece of warm electronics if you deem necessary.
I even microwave it myself for a few seconds when I come into the office in the winter with heat turned down. You do have to watch it closely though when you do that
Not recommended for any other compound, I absent mindedly microwaved a metal oxide compound a couple years ago and had a nifty little toxic fire going, it was pretty exciting lol