Software is the key

Twisted, I have done it as Yoda says as well, and I am not an expert but I have been lucky using a third party software to store my waypoints from one of my Garmins and send them to another one. I used an older Delorme TOPO mapping software program (V4.0 at the time). Cost for the software was around $75 - $100 but I used it to store wayponits and create maps for the different areas I hunt in different folders so I only transferred the waypoints from that area and not all of them at once. Made it easy to manage, and the software did not seem to care what GPS I used - it simply pushed and pulled the information from whatever I had plugged in to my computer. It would not send or recieve maps, only waypoints. This process allows you to clear your GPS and only have what you want on it without losing everything else - just remember to copy it to a disc for backup on occasion. Good luck.