How do I clean my white railings on my porch?

Are they wood, plastic or painted metal?

Kandace...We use Krud Kutter (Lowe's) and a pressure washer on our vinyl.

I have a go to for so many things. Awesome is a spray cleaner for $1 sold at many Dollar stores. My neighbor purchased a cleaner for his siding for $27 for a bottle and after rubbing and rinsing it was still dirty. I got out the Awesome and sprayed it on the siding. It rinsed clean. He stood there with his mouth literally open. He took his cleaner back to the store. I love this stuff. Anything that has hard remove dirt and stains and greasy things like kitchen cabinets where they get sticky around the handles. This stuff is really awesome.

Heavy Duty Mr. Clean Magic Eraser, followed by a hosing down to remove the residue.

Easier with two people if done this way and rather messy, but very effective and not hard. Big bucket of soapy water and a scrub brush or broom. Slop soapy water over it, scrub it with the brush or broom and have the second person hose it off well while it's still wet. The hosing off while wet is the key as it helps keep the dirt and dust from settling back into cracks and seams and whatever texture might be there. If you have a third person who comes along and wipes it semi-dry, so much the better.

Use a Heavy Duty Mr. Clean Magic Eraser