Freeing buses

I know I can set a high number of buses, but what if I would just like to free some buses that are no longer in use, and no longer have a reference to the bus in the form of a variable, etc.? I haven’t been able to find a “free all buses” method. Is there a bus array somewhere that can be wiped? Or do you have to reboot the server to get rid of buses?

It’s a Server method, e.g.:

s.newBusAllocators