Directly setting shift, alt, ctrl key state to OFF

I see some posts that refer to a way to do this, but I can't find anything that actually addresses it. The application I'm working with has a very poor user interface and I'm using scripts to speed up data entry. Occasionally the alt or control key (or both) seems to get stuck and causes users problems. I would like to have a programmatic way to force the shift state of those keys to off. I can't figure out how to go about this. Has anyone out there solved this problem?

Thanks in advance for any help you can give.

Send {Alt Up}{Ctrl Up}{Shift Up}

Wow! Almost TOO simple! I was expecting some kind of DLL call or some such.

Your help will help me make several people happy. Thanks very much!