I do what others have said, but I also put some packing tape on the envelope to prevent the hard edges of the toploader from ripping the envelope. I tape the toploader to the envelope, too, to keep it from sliding around in the envelope. And finally, I ship it with a surcharge (20 cents more) to prevent it from going through the auto stamping machine, which can shred envelopes with toploaders in them. I may overdo it a bit, but in the past I've had issues with ripped envelopes, even to the point of the cards being fully exposed, so better safe than sorry.