You can drill it and use an easy out. If it is a big screw I have used a punch and hammer to drive the screw loose by hitting it on the far side in a counter clockwise direction.
Ways to remove a stripped screw: Create a notch which you can fit a cross-cut screwdriver into using a metal file. This only works if the screw head protrudes enough to get the file into it. Drill out the head of the screw, remove the part it was holding in, and use the new angle to try and remove it. Carefully fix a rod to the screw itself (using glue) so that when you turn the rod the screw turns with it. (This runs the risk of gluing the screw in permanently unless you're good at precision).
An Allen screw is a screw whose head has a hexagonal socket.
drill off the head remove whatever it held down use vicegrips to remove the rest becarful not to drill to deep or brake the saft off or youll have to drill and tap out the hole for another size screw
eat it
drill screw head out with 1/4 " drillbit mirror mounting plate can be removed by removing door panel. replace with new monting plate if threads are stripped in mounting plate. just did this myself
To remove a pressed-in stud, you usually stack up a few washers and crank the stud out with an impact wrench on the nut. If the threads are completely stripped all the way down, you may have to take the head to a machine shop and have the stud drilled out and tapped for a screw-in stud.
If the screw is stripped then the threads are not holding and can be removed with pliers. If your asking, about the head being stripped, then you take a hack saw blade and cut a new slot in it,this way you can use a slotted screw driver to remove it. If it is locked in and does not come out, you will have to drill it out with a drill bit that is smaller then the thread size.
Here are 3 options for you at this point: 1. Bring the head into an automotive machine shop for them to repair it; 2. Repair the stripped hole in the head with an insert 3. Buy a new head, rebuild the engine from the head gasket up.
Avoid making the problem worse. If the tool you are using is slipping, stop using it immediately. Further slippage will only continue to wear down the screw head and make it harder to remove. Definitely be sure you are going in the correct direction for removal, which is usually--but not always--counterclockwise ("righty tighty, lefty loosy"). Pressing down hard as you are unscrewing will help prevent slippage
Hopefully you stopped once you realized it was stripped. If you did then your best option is to use a T7 driver and first tighten it (turn it clockwise) so that it can grab onto the un-stripped portion of the head. Then turn it (anti-clockwise) to loosen. Hope this helps. I tried this on my stripped screw on the Juliets and it worked. If it is stripped real bad and you went at it a few times then ideal would be to walk into an optical store and see if they can do it for you. cheers!
There is a type of bit that can cut into the remaining screw head that may help, but otherwise the screw needs to be drilled out.
It should UNtighten counter from the rotation of the head. If head rotates right then unscrew left.