My technique, using common household tools (OK, stuff sitting in my garage), is to use a paint stirrer to depress the spring and follower (it is plenty long and gives you lots of leverage and it fits perfectly between the feed lips of the mag). Once the spring is depressed, put a golf tee (a lot safer if it goes flying than a screw or nail) in one of the witness holes to hold the spring down. That should leave the follower loose and you can shake it out of the top of the mag tube. Next, put your thumb over the top of the tube and remove the golf tee from the witness hole. The spring will expand, make sure you stop it with your thumb. Remove the spring, be sure to remember the orientation. There is a top and bottom, and a front and back to the spring. Make sure you put it back the same way it came out.