By default any clipart from OCAL issued in Public Domain (<a href="http://en.wikipedia.org/wiki/Public_domain">http://en.wikipedia.org/wiki/Public_domain</a>) i.e. you can use it for any purpose, commercial, non-commercial or whatever. <br>
<br><i>NB - now default license is CC0 (<a href="http://creativecommons.org/choose/zero/">http://creativecommons.org/choose/zero/</a>) - it is very close to meaning of PD. You're still free to use it in any application.</i><br>
<br>Of course, sometimes users of OCAL (especially new ones) not catch that all work they submit to OCAL automatically goes to PD (CC0), so sometimes copyright issues appear. <br>In this case, Gerald_G is well-known contributor, so you can use his clipart without any concern about copyright problems.<br>
<br>Anyway - your decision to contact author for more confidence is more than praise!<br><br>HTH, Oleg. <br><br>P.S. Welcome to community!<br>