Door hinge pin retaining clip

[rizmo]

The retaining clip has fallen off the lower hinge pin of my driver's door. Found out just as the pin was about to come out, so knocked back in, but no sign of the clip. Locally, I am unable to find anyone who can give me the size or type, nor where I can buy just one (I don't need a dozen!). Anyone had to get one, and can guide me in the right direction?