Depends how much you want to spend and how long you want the finish to last. Getting them powdercoated would probably cost getting towards the cost of a new set.
Quickest and easiest would probably be quick drying spray paint - smooth even finish. I have used Dulux Spraypak Quickdry Enamel (which most DIY stores should stock) on some car parts and it goes on nicely and dries quickly meaning you get the job done a lot quicker.
Give them a bit of a sand to help the paint adhere then clean off any dust. Lay them out on a bench with newspaper underneath (somewhere where it won't matter if there is overspray ie not in the house!). Wear a good quality mask with a cartridge suitable for gas. Dont spray too thickly in one go - thinner coats, built up, is best.
The finish wont last forever whatever type of paint you use yourself. If you are careful not to bump them into each other too much, you should be able to minimise chips. You can always re-spray if they get bad again.
Spraypak colours: Range of 11 (gloss) colours plus 3 metallics, flat black, clear and undercoat.
PS: Gloss shows up more imperfections, so surface needs to be very smooth and sprayed evenly.