[bredin01]

I am working obn replacing an outdoor lamp fixture. The wires are older and unmarked. How do I tell which one is hot and which one is neutral?

[Stratmando]

With power off, disconnect wires, not touching anything, turn back on, then a meter with a ground connection touch each wires and look for voltage, Turn off and identify.
You could use an extension cord plugged into a grounded outlet and use end of cord for a ground reference.