Can I test my oil mixture by looking at the plugs?

So I have my sled in a somewhat usable shape. I just recently purchased it and haven't used it yet. But I kinda need to use it this weekend and I haven't cleaned the carbs yet. It starts nicely and runs nicely.. but how can I be sure its not running lean and is going to melt down? Can I clean the plugs, then run it for a bit, then look at the plugs for signs its running properly? Or something like that?

Thanks

Can I test my oil mixture by looking at the plugs?