The pot I use to make ricotta in has a heavy buildup of milk scale.  I sanded it out last year and it’s building up again quickly.  I’m not sure what my pot is made of.  Magnets stick to it, so I think it’s steel of some sort.  I don’t know if the scale buildup is inevitable, or if it could be prevented either by a new pot or by a different cleaning material/process (now I just use hot water and soap). 

I’ve read that stainless steel or enamel are best for cheesemaking.  Could my pot be magnet-attracting but not stainless steel? If I buy a new one, do the differences in weight and quality between different models of stainless steel or enamel pot make a difference for cheesemaking? (I use a 2-stockpot double boiler type setup for ricotta, so a thick bottom shouldn’t matter.)  Do any of you have particular models that you would recommend, or warn people against?

Should I expect this kind of buildup even with stainless steel or enamel? If so, how should I clean it off?

For cleaning I would suggest a scouring pad of some sort - at least periodically.  I use a thin walled stainless steel pot, in a water bath.  I also have an enamelware pot, but I only use it for sterilizing my equipment.

the problem with sanding/steel wool etc is that the tiny groves that it creates is a Magnet for particles. I use one of those enamel canning pots, its wide so easier to cut the curds, cheap too, I just use a standard dish brush to clean them, if u burnt something on it then soak it in vinegar.

When you rinse the milk or whey out of the pot, start with cold water and scrub with a sponge. Then, you can use hotter water and some soap. I’ve found that if I rinse immediately in hot water the milk scale problem is worse. I’m with Neil on using something that might leave small valleys or ridges in the metal—a nice place for bacteria to hide! Although, prior to using my pots (or spoons, or thermometer, etc) I spritz them inside and out with a diluted bleach solution, let it sit for a few minutes, then rinse with cold then hot water.