What kind of marks? If they're from dirt/oil/grease/road-tar/bird-poo/squirrel-guts, then you can dissolve it with the appropriate solvent. Some stuff works best with an aqueous ionic solvent, others with a non-polar stuff like thinners. If the marks are scratches... that's tougher because they're below the surface of the tubing. You can re-create the brushed finish in the scratch by scuffing it up, steel-wool works well.
The best way I've found to wash any glasses is to use dishwashing soap. It works great. Let the glasses clean and doesn't harm the lenses, wash them in your dishwater, before washing any of your dishes. they can really do a great job on your glasses.
Washing down with warm soapy water with a soft cloth. After the frame has dried then some anti-corrosion/dirt spray could be used to help keep the frame cleaner for longer.Rather than using expensive and unnecessary cleaning products, use soap and plain water to clean your eyeglasses. To reduce the amount of buildup on your lenses you should clean your glasses deeply at least once a day and touch up throughout the day as needed. Use a gentle soap; dish soap works great.