Often where you see 30A plugs burned, BOTH sides of the connection are damaged. And, they should BOTH be replaced.
The advice above about trying to figure out WHY the plug is burned is a good one. Dirty, loose, otherwise poor connections? Trying to pull too much current thru the cord?? IMHO, 30A connections are incapable of sustained 30A service delivery, unless brand new and shiny, tight connections, cool weather, carefully monitored, etc.