Once the key is removed, use compressed air to blow away any debris around the key retainer.

To remove any grime buildup around the key retainer, wet a q-tip or a cotton swab with isopropyl alcohol and wipe the area.

If the key retainer is sticky, remove it and soak it in hot, soapy water for 5 minutes, then let it dry and replace it.

Note the orientation of the key retainer before you remove it!