I had a couple pots and couple pans with loose rivets, to where the handles wobbled.
I fixed all four of these in less than 5 minutes. They are as good as new now.
Tools needed:
1) Hammer
2) Lodge cast iron pan
Directions: Lay cast iron pan flat on counter face down. Take a pan, turn it on end and rest the exterior part of rivet on the surface of the bottom of the cast iron pan. Hammer the rivet on the inside, very carefully taking care not to dent the pan. The rivet on inside will flatten a bit as you hammer it, and tighten it right up. It might take several hits. I was very slow on upswings to take care not to hit other side of pot/pan.
I saw this tip on youtube from a couple people, but they suggested using a vice for the hard surface to hammer against. I didn't have a vice so I got clever and used a lodge cast iron fry pan turned face down on my kitchen counter top.
https://www.youtube.com/watch?v=jpavumjIyJchttps://www.youtube.com/watch?v=hfZVNCKrVb8 (antoher way)
EDIT: The cookware I fixed were 4 very nice pieces of clad pots/pans. One was solid copper on the exterior, stainless on the interior. The other three were Cuisinart Multiclad Pro.