[RodB]

Paper/wax caps don't have a polarity, one end is usually marked to designate the "outside foil" so you can attach the wire lead from that end to the lowest impedance part of the circuit. This is effective in shielding the circuit from outside interference. You'll notice the black ring around the end of the cap. That's the outside foil end. The only problem is your new cap isn't marked. There are several ways to find which end should be marked but you might not care to take the time to do this. Go ahead and plunk the new one in either way (Some purists will cringe). I use an oscilloscope attached to the cap, hold the cap in my fingers and look at the level of noise the cap displays then reverse the leads and observe the level again. The lead attached to the ground wire of the lowest level of noise is the outside foil.