klj2497,
If it were me, which it's not, but if it were, I would ditch the relay. The metal is not meant to be "sanded". It won't last.
If contacts are dirty, I would normally drag a dollar bill soaked in DeoxIT across them to clean them. Sanding will only drastically shorten the life of the contacts.
There is a plethora of relays available on the market. Identify the coil voltage needed and order one. Yes, current capacity is important. I don't know enough to calculate RF current needed for the relay but I have used a 4PDT relay in the past to replace a 2PDT relay and simply doubled up the contacts to "double" the current capacity of the 4 Pole relay. It may not mount exactly the same as the original but if there is enough room in the chassis (physically) you can find a way to mount a new relay.
To extend the SSB dropout time of the relay, follow the AM/SSB switch wiring to an electrolytic capacitor. (It should "add" the electrolytic to the circuit when in the SSB mode.) Increase the uF of the capacitor to extend the "dropout" time and decrease the uF to shorten the "dropout" time.
Good Luck!
73's
David