Since you've tried the over the counter method, I would agree with Bobbi. Hire a pro. Those sinks are so pretty refinished to their original state and a pro will give you a finish that will last the rest of your life. If you can't find anyone listed in the phone book, ask around at a hardware store.

Just make sure whatever you install is able to be opened from the inside for getting out in case of fire. If you are the only house on the block with bars, it often draws savvy thieves as they wonder what you have in your place. If most of the block has bars, put them on too. Because then the lazy thieves will not go after the easy pickings, your place. I've been in big urban where both were true, either one or two houses on the block had the bars and they were targeted; or everyone pretty much did and whoever didn't got lots of breakins. One house I rented that had bars, they had some funny latches the landlord had to show me how to work, so I could get out of the house if I needed to for fire. It was code, the latches.

I agree with divadeva. More lights. If you can add pot lights do it. If they're already there add task lighting and up the wattage on the bulbs on the pot lights (replace with LED and you can make them brighter because the wattage on LED is lower for brighter light). If you have all of that add decorative lighting. If ventilation is an issue find a way to move the air around or add air filtration. Maybe the HVAC is deficient. Maybe you can add a HEPA filter instead of the standard one that comes with the unit. Call an HVAC specialist to see if there is a way to boost air flow in the room.

You could integrate a single automated mechanical chair System on to the side of the railing which the Elders could use with ease. And you don't have to modify the existing staircase. And I can technically give you a working solution if you are interested. Contact 8073342913