Unusual cookware question. Is this safe?

[Toposlonoshlep]

Hi,

This is going to sound really strange if you've never lived in an old steam-radiator heated apartment.  Our air is horrendously hot and dry because we cannot regulate our heat for obvious reasons. We have 2 large aluminum pots, which we don't use for cooking (I invested in safer cookware). We have been filling them with water and putting them on top of the radiators to make the air more moist. I have noticed that there is residue when the water evaporates. Is it aluminum oxide? Is it bad? I am wondering if it is releasing something into the air when heated?

I know not to cook in these pots so aluminum doesn't leech into the food, but could it be releasing crap into the air when heated?

Thanks ahead of time!

[Marissamom]

do you have hard water? because if I do something similar it leaves minerals behind. 

[Toposlonoshlep]

Originally Posted by Marissamom 

do you have hard water? because if I do something similar it leaves minerals behind. 

We have city water, so it is definitely pretty hard. I am hoping it's just the water and not the aluminum releasing nasties into the air...

[leighi123]

why not just buy a humidifier? 

[Toposlonoshlep]

Originally Posted by leighi123 

why not just buy a humidifier? 

Trying to keep the electrical bill lower. It is definitely in our future. This is just a simple, direct solution for now.

[Chamomile Girl]

I second the hard water vote.

[violet_]

It's definitely mineral deposits. Metallic aluminum doesn't react with water. 

[lunarlady]

Another vote for hard water. Aluminum reaction would cause darkening and pitting, not deposits. Keep the cheep humidity going!