Restoration attempt-any advice ?

 For quite sometime I had been working hard to restore six following pens. But the damaged plating on the metal ares are not possible to restore, particularly on the Aluminum based metal 
caps and other parts like clips. By hand polish this is the maximum extent that could be restored as shown in the photos.   I wish a spray on plating like paint or a brush applicable gold emulsion 
were available- but no idea where to look and how costly. Requseting viewrs with jewellery knowledge to kindly advise.

The pens are : Whitefeather 608, Plato 222, Wilson Commander, Hero 240, Pilot Japan gold nib , Optimat- in same order as the photos.