You have the choice of working harder before you paint to mask off the glass, or working harder after you paint to clean off the glass.
Most of us will use masking tape. Be aware that there are different grades of glue on masking tapes.
The Painter's tape has a lower tack, it sticks less, which could be very important if you are taping on freshly painted surfaces. Never leave tape on for more than two days, especially if it is in the sun as it will harden and become a big problem to get the tape itself off.
Let me share with you a great little information sheet that I received from the 3M company about painter's masking tapes.
Some tips when using 3M Scotch Brand Painter's Masking Tape:
AVOID STRETCHING TAPE: The backing is designed to conform to curved surfaces. Should shrinking occur during use, it is desirable to have some stretch left in the tape.
UNROLL AND PRESS DOWN TAPE A FEW FEET AT A TIME: Pull tape off roll a few feet at a time, press down a small area, unwind a few more feet, tape that down and continue. Once the entire length is in place, the remainder of the area can then be firmly applied.
LAY TAPE INTO SURFACE DEPRESSIONS: Tape has stretch limits. If it is stretched and forced down, the tape may lift up, or in come cases, break.
PRESS EDGE OF TAPE DOWN FIRMLY: This will help prevent seepage and jagged line separation.
ANGLE OF REMOVAL: 90 degrees is most satisfactory. As the angle is increased or decreased, additional stress on the adhesive can cause transfer.
SPEED OF REMOVAL: Moderate speeds are best. Too fast may cause slivering. Too slow increases tendency to transfer adhesive.
TEMPERATURE OF REMOVAL: Warm (15 - 35 degrees C) are recommended. The adhesive is firm enough for clean removal and yet is not so firm as to cause slivering.
3M Company invented masking tape in the 1930's as a product for the automotive industry. The advent of masking tape allowed for the introduction of the first two-toned cars. Since that time, we have developed over one hundred different types of masking tapes for almost every paint or decorating application. A masking tape's toughest job is, in fact, paint masking. The tape must: * Apply easily; * Adhere firmly to the surface it is protecting; * Give a sharp paint edge; * Remove from the surface easily. For a tape to perform well at paint masking, it needs a balance of properties in its construction.
Masking tapes are basically made up of three components: backing, adhesive and release coating. 3M Scotch Brand Painter's Masking Tape is specifically designed for paint masking applications. The construction of this tape has been tailored to achieve the correct balance of properties so that the product works best for this application.
A note about utility-grade masking tapes: These products are not recommended for paint masking. They can be used in non-critical applications such as bundling, labeling and box-sealing. However, they tend to leave poorer paint edges, do not remove easily and are more prone to "bleed-through". These all end up costing the painter more in the end, because more time and effort are wasted cleaning up and re-doing the job.