Not really sure where all this aluminum poisoning stuff came about, but I've been using aluminum for years (we all have) and unless someone out there posts some imperical data concerning Al oxide poisoning and foods, I'm keeping my pots and pans. I like my teflon one egg wonder, but still love my zombie pot!
I also heard that if you put mashed potatoes in the fridge too soon (while still warm) it'll poison the batch and you'll get sick when you dine on leftovers.
I think it's a bunch of hooey!
If it was actually bad for you there would double blind reproducible studies that were published it reputable scintific journals.
I use SS pots/pans to cook at home and in the outdoors not because I think aluminum is gonna make me sick one day but because I just find the food has a better taste when I cook in a SS pot/pan.
On the other hand, the mashed potato thing can be real; it depends on the size and shape of the container. What you're looking for there is to cool the potatoes down to 70 F within two hours of it dropping below 140 F. From there, you have another four hours to get it below 41 F. At least, according to USDA regs (which are conservative as all get-out, but make at least some sense).
The reason that it's an issue--especially with things like mashed potatoes--is that the center of the potatoes, if you don't spread them out into a thin layer, doesn't cool down fast enough. Which allows the potatoes to sit in the "danger" zone for temperatures, where bacterial growth is at its highest. Which increases the possibility (it's still unlikely, especially if you reheat them to 165 F for 30 seconds at the center) of food poisoning.
Hope it helps!
But if you can't remember how to get home after your camping trip don't blame us.
I wouldn't worry much...heck, all those old boy scout mess kits were (and still are) aluminum.
Don't worry about the AL cook pots. And good on you for "recycling" a pot from the thrift store--one of my favorite places to shop.
After I send my boys home to the mother I'm hitting up salvation army!