I would like advice on an easy way to paint old vintage metal chairs.

Hi Jac, spray painting would be easiest. You want to brush or sand off any rust and loose existing paint to get a smooth surface. Then wipe the chairs down to remove and residual dust from the prep work you just did. Then spray paint (outdoors is best for spray painting - or in the garage - it goes everywhere if you spray indoors and has some fumes). Rustoleum makes many different types of spray paint that adhere to metal and come in many colors.

Hi there, the thing with metal is getting it as clean and stripped down to the bare surface as possible. After that a good metal primer and paint like Rustoleum makes will give you a product that will last a long time!