Materials Required

Paint Thinner and Putty.

Putty Removal Part 1

Start by removing all loose and cracked putty or glazing from around the windows, you can do this by inserting your screwdriver into a crack and prying until the loose putty comes up.

Putty Removal Part 2

Place the top of your screwdriver at the edge of the putty; lightly strike the handle of the screwdriver loosening the putty, ensure sure the tip of the screwdriver is angled to the side, not facing the glass and continue this until the putty is removed.

Brushing the Bits Off

Now that most of the visible putty is gone you can use a paint brush for the removal of the particles of putty.

Applying the Putty

Apply some putty to your knife, place the tip of your knife against the glass along the edge of the frame, and begin at the bottom-left side. Press the putty onto the window frame and pull the knife down away from the window on a 45 degree angle, do this until the window frame is filled.

Smoothing the Putty

Clean your putty knife, and hold it with the blade facing to your left. Tilt your putty knife at a 45-degree angle. The high point should be closest to your glass. Use your putty knife to smooth the putty out by dragging it.

Cleaning

Finally, carefully use your putty knife to remove excess putty off the glass.