My dad taught me to use a hair dryer on a sticky lock last winter. Honestly, the best fixes are usually just simple tricks with stuff you already own. It feels like we forget that now.
My old landlord showed me the hair dryer trick for a frozen car door. It's wild how many problems can be solved with stuff from the kitchen or bathroom, like @mia_fox98 said. I guess we just get used to buying a special tool for everything now.
30 degrees F is actually the real cutoff for hair dryers on car locks. I learned that the hard way after trying to thaw a lock in single digit weather and it did absolutely nothing. The hair dryer works great for shellac runs because shellac melts at a lower temp than most people realize. It's like 150 degrees F or something, way lower than polyurethane. But yeah for frozen doors you gotta get the temp up above freezing first or you're just blowing cold air at cold metal.