how do i restore old bathtub with rust/lime/calcium deposits?

If your speaking about "restoring" the tub then this is one question, if you simply want to "clean" the tub, this is something different.

To "restore" it, the tub. Go to Home Depot, get the tub restoration kit, it's $35.00 and comes in various colors. You'll need a palm sander, it all depends on how much work it entails also. If you have large dents and nicks then, you'll need a fiberglass kit, a small one from either Home Depot or a auto store from your area.

Be careful, take your time and do a good job, that's all that's required and be patient.

For simple cleaning, use lots of elbow grease, it doesn't matter by now but, you can use cleanser or something stronger to get the rust out, even steel wool.

huh

Rust away doesnt work?

You may need a quick sander to get the rough spot out

or talk to someone at Lowes or Home Depot

goood luck