You make a "V" shaped tool from coat hanger wire. If you have a new tumbler in front of you, you can see how the tool is inserted and how it depresses a spring clip near the base of the tumbler.

Check out these threads:

http://www.peachparts.com/shopforum/showthread.php?t=158328&highlight=glenmore

http://www.peachparts.com/shopforum/showthread.php?t=110367&highlight=glenmore

glenmore
1991 300CE
2000 C280
1990 LS400