This is what I do to clean the lockdown bar receiver assembly:
I unbolt the assembly from the machine and take it over to the kitchen sink. Now I spray it down good with "Mean Green" household cleaner and let set for a couple of minutes. Now run a sink full of warm water in the sink to soak the complete assembly in it and start scrubbing it with an old toothbrush. Now rinse off and blow dry.
If the assembly is rusted, now you will run a sink full of warm water and a 50% solution of C-L-R cleaner and water. Let soak a few minutes and then scrub it with a brass bristled "detail brush" commonly found in hardware stores and Harbor Freight Tools. Now rinse off with warm water and blow dry.