Here are some tips that you may find useful. I do these things all of the time, and never really give it a second thought.
Whether youíre at the local post office or like me, breaking down old mint stamps into plate blocks and scrap postage, there is a small trick to getting nice, clean looking plate blocks with even edges.
In some cases, the perforations (or die cuts) extend to all edges of the paper. Itís easy to remove these plate blocks. Crease the stamps forwards and backwards to break the paper fibers. This weakens the paper. Tear the stamps apart in one direction, then the other direction. Because the perforations go all the way to the edges of the paper, you should have no problems getting nice even edges on the plate block.
What about the issues where the perforations stop short of the edge of the paper? You have a quarter to half inch of paper to tear. There is a little trick to getting the paper to tear nice and even.
In many cases, the perforations will extend all the way to edge of the paper on two of the sides of the pane, but the other two sides, the perforations stop short of the edge.
Starting with the side that has the perforations going all the way to the edge of the paper, crease the stamps along the perforations several times by folding the stamps forwards and backwards. That weakens the paper fibers. When you break the stamps apart along the perforations, you get a nice, clean separation.
If you donít crease the stamps along the perforations and you just begin to tear the stamps apart, the stamps SHOULD separate along the perforations. Thatís why they are there. But if you donít crease them, the separation may not go smoothly and you end up tearing into some stamps. And Murhpyís law kicks in and youíll end up tearing the stamps in the plate block, and not the stamps that are scrap postage.
Now that you have one side of the plate block separated, crease the stamps again on the edge that has the edge of paper without perforations. Here is the trick. Start tearing along the perforations to the edge of the paper. By the time you reach the edge, you have a smooth flow going and it should tear straight across. If you start along the edge of the paper, there is a chance that youíll tear crooked when you start, destroying the plate block.
What about the more modern issues in these mini-sheet formats where the perforations donít extend to any of the sides of the paper? These are a little tougher.
You can crease the stamps again along the perforations and start tearing them apart. However, there is a better way, but it takes a little more time and you have to be careful because it involves using scissors.
For these issues, crease the stamps along the perforations as you normally world to separate them. Using a pair of scissors, start at the edge of the paper and cut as straight as you can until you reach the first perforation hole. Then stop. You may want to use the scissors to but the second edge of the paper too, again stopping when you reach the first perforation hole. Using the weakened paper fibers from creasing the stamps, now you can cleanly separate the stamps.
I donít recommend using scissors to cut apart the plate blocks along the perforations. Each perforation (or die cut) is a tiny bump in the paper. If you cut with scissors, there is a tiny pattern of bumps that can throw your hand off. And before you know it, youíre cutting into the stamps and not along the perforations. Even with a really steady hand, I donít recommend using scissors all the way around.