Assuming there is another car in the house, just take the tire to the shop.

 

I make sure my Schrader valves are properly tightened. Here's the correct tool:

 

So glad I found this! My 911 is parked for the winter, but just noticed yesterday the rear passenger tire is totally flat. After inspection, it's the valve that is leaking. Hopefully this will do the trick. Don't want the hassle of jacking up the car to take one fricking wheel in for repair