How do I clean the metal shield on stairs?

They are a pain! Warm soapy water and a stiff scrub brush.

This information should help:

https://upsideinnovations.com/how-to-clean-aluminum-stairs/

Using an old stiff toothbrush and some warm soapy water may do it!

I usually use an old toothbrush too, but if that doesn't work, try some fine steel wool or a steel wool soap pad.

You can purchase steel wool brushes in various lengths and sizes, I think that would be perfect for this!

spray with Fantaskic cleaner, scrub with old toothbrush then wipe away the grime - also Mr Clean Magic Erasers will work on this

Yes, steel wool or wire brush. Something like this:

https://www.amazon.com/Brushes-Stainless-Scratch-Automotive-Cleaning/dp/B07F3YYB2D/ref=sr_1_3_sspa?crid=13GATVW22R6QV&keywords=steel+brushes+for+cleaning+rust&qid=1583867909&sprefix=steel+brush%2Caps%2C138&sr=8-3-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyNjI1VUNaU1NNOENNJmVuY3J5cHRlZElkPUEwMzU1MTc3REZVMFE1MUZaTDdFJmVuY3J5cHRlZEFkSWQ9QTAwNjU4MTAyQ01ZVjM0MVZVVjMyJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

Just don't use vinegar with steel wool. This turns into a stain. I accidentally did that one time. lol.

Thank you I will try and let you know!

I use young living thieves for everything: https://www.aratariathome.com/blog/non-toxic-switches-we-have-made

Awesome spray cleaner from the Dollar Store and a toothbrush. Rinse well. Awesome removes dirt other cleaners don't touch.

easy off oven cleaner....works like a charm.

you can also use to clean glass/plastic shower doors to make them look brand spankin' new

I have several cleaning tutorials that might help you https://chascrazycreations.com/diys/how-tos/cleaning/