I'm with Dana in saying that it's difficult to have too many lights. However, if your really do consider them to be excess inventory, then you should still think about keeping one or two of each type around for teaching purposes. As your students move on to other facilities they won't always get to use the newest and shiniest, so having experience with a wide variety of lighting instruments can give them a better understanding of the advantages or limitations that each product offers. Side-by-side comparisons can provide a better understanding of how and where each type of light source can be useful (this can be good assignments for extra credit reports, too).
It can also be quite educational to dissect a few of these to see how the inner workings are arranged and to exemplify how wiring can become frayed and dangerous. Also consider scavenging parts from several similar fixtures to make one or two whole fixtures.
From a safety standpoint, it is advisable to go over each fixture and make sure that all of the electrical connections a secure and properly insulated from the fixture chassis. This is particularly important if you are going to pass them on to another school in your district. If the school district is going to handle the disposal of excess inventory by gift or sale to another entity, then the fixtures should come with an "as-is, no warranty expressed or implied, use at your own risk" disclaimer.
Go to the PLASA / ESTA web site (http://tsp.plasa.org/tsp/documents/published_docs.php) and download ANSI E1.32 - 2012, Guide for the Inspection of Entertainment Industry Incandescent Lamp Luminaires
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Erich Friend
Theatre Consultant
Teqniqal Systems
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