I bought my cable luber at the local motorcycle shop, and it included the cleaning/lube spray and the attachment for the cable end. Attach it, give it a 3-5 second spray.....job done.
http://www.protectall.com/cablehowto.aspxAlso, you should remove the lever, clean the pivot bolt and bushing in the lever, then put a small amount of a light grease on the parts, and put them back together. Same with the lever on the master cylinder for the front brake, and the rear brake foot pedal, cable and shaft in the rear brake pedal....and the foot shift lever and linkage.
These parts are often overlooked.......and you really should be cleaning and lubing them once a year at a minimum.