When the box was sold new it came with two pieces of spring steel that slid in between the slide and drawer to release the clip. The tool was about a six inches long and about a 3/8” to 7/16” wide with the ends bent up a couple degrees. You’d open the drawer all the way then close a little slip the tools into both slide and pull the drawer out.
I took the hanger out of a hanging file folder, cut it in half bent a slight angle at one end, and aBout 90 at the other, works a charm. Posted pics in one of the other threads on this sMe topic.
This is what you need. The small one is the Snap On drawer removal tool. The longer one is a modified hacksaw blade. Either will do. You insert it between the slide and the drawer and hold it over the drawer stop so you can release the slide from the drawer. Once you do a few you'll get the hang of it. I've done a ton of these, but even so you can still run into one that will have you cursing under your breath.