how to tell differnt styles of rim?

[Kyle L]

so i just got a job change and balancing tires, and other easy thing. i know what im doing and everything but the only problem is when i balance a tire there different kind of weights for differ kinds of rim. i have trouble telling if there steel or alloy rims or any other kind. we got like a five different styles of weights. ever time a i ask some one there what kind it is they make fun of me. is there any kind easy give away i can look for to help me. please help im not an idiot i just cant tell the differences