Found an old LCD in an old radio, how to test it?
It is probable that there are more segments than wires.

If it is a 4 or 6 digit display, there will be 1 connection per digit and 1 per segment common to all digits. So when you get one segment to darken, move one connection around. Either different segments on the same digit will flash, or the same segment on different digits. The other connection will have the opposite function (if the first changed digits, the second will change segments) Quickly you can identify and write down the pattern. There may be a "spare" segment bit or two that light up odd bits of display (AM, FM, colon for clock, etc) according to which digit is driven.

A basic LCD is actually AC driven, so if you can arrange about 3V AC (square wave is best) at 50 or 60Hz, say from 2 Arduino pins, (or one pin via a capacitor) that will be a better test signal than Andy's 1.5V battery (though the battery will work well enough for quick tests)

Having identified the pattern, writing a program to drive the LCD will be an interesting exercise...