No matter how simple the repair, it seems like there’s always one stuck screw. You try to muscle your way out of the jam, but all that does is cam out the screw head slots. It doesn’t have to be that way. Here are a few tricks to coax out a stubborn Phillips screw.
At the first sign of trouble, spray the screw with rust penetrant (Liquid Wrench and PB Blaster are two really good brands). Let the penetrant work for at least 15 minutes. Then spray it again and tap the screw head dead-on several times with a hammer. Then try the screwdriver again.
Next, apply valve grinding compound (photo 1). The compound (about $4 at any auto parts store) contains a fine grit that helps the screwdriver bite into the head.
If the screw still won't budge and the surrounding surfaces can tolerate some heat, aim a lighter flame directly onto the screw head. Then douse it with cold water before trying it again. Still stuck? Invest in an impact screwdriver (photo 2). Pick one up for about $20 at a home center or an auto parts store.
If you've stripped out the head, cut a new slot with a straight-groove rotary tool (photo 3). Then crank it out with a flat-blade screwdriver.