alginon77
best thing to do it get a basin to put the grills in then coat them on cooking oil then fire up BBQ wait till red hot (not a lot of flames) then replace grils from basin (watcheyebrows) then it will burt off all the crud and give you a nice top to cook on again i did mine yesterday and have just fired up for the 1st BBQ of the year 30 min ago

nigel the builder
GIVE A GOOD SCRUB WITH SOAPY WATER scowering pad get rid of all the rust etc,thouroughly dry off,THEN,coat with cooking oil etc,hope this helps

don n
Brush them good with a brass bristled brush until almost all of the rust is off of them. Then take some terry cloth towel and cooking oil and wipe the rest of the rust off. Heat the grills over the burners or coals for a little while to season them.

cheezy
clean them off with an sos pad, rinse, dry, coat them with oil & bake them in the oven @ 300 degrees for an hour