This actually works pretty well if you don't clamp it down. Just put the figure in a neutral position, such as on it's back, and put in the freezer immediately after it's been well softened in boiling water It kinda makes the plastic snap back into it's original position. If the joints are loose due to stretching and distortion this works the best. If the joints are loose because they are worn down or ground down from constant use than you'll have to use a material that will fill in the area that was worn off the original plastic. That's where the Super Glue comes into play.
Both methods can damage the figures finish. The Super Glue can stain and fog but you can reduce this affect by cleaning as much excess from the visable surface as quickly as possible. This is easier than you think because it dries a lot slower when it doesn't have a second surface to bond to. Careful because whatever you use to clean it actually becomes the second surface so you have to be quick all the while still working the joint to keep it from freezing. I usually just use my finger. It's non-toxic and you can get quite a bit of it off, just don't leave it on there too long or you become one with the figure.
The boiling method will remove the oils that they put on the figures before packaging. This oil is necessary to preserve the exterior finish of the figure and must be replaced. If you only submerge only a part of the figure it may very well look different from the rest of the figure when you are done. This is most noticable on darker colors and glossy finishes. The best way to reduce this is to get the figure back to a neutral temperature as quickly as possible, (try running room temp water over it, drying it and letting it sit for 10 - 15 minutes) and then (honestly) rubbing the figure with vitamin E enriched lotion or skin cream and removing it as quickly as possible. You may have to do this with the entire figure to make it match. I actually do this to some of the figures anyway to give them a little bit more depth, almost like a wash. Try it with Black Manta or Superman. I bet you'll like the way they look.
The boiling method works very well to correct distortion created by packaging as well which happens a lot with DCUC. Most of the time the figure will return to it's natural position after it's been softened by the water, but sometimes you have to hold the part into the desired position and run cold water over it, then place it in the freezer.
Sorry to be so long winded, but I know how particular I am about my figs and I have to do a little bit of adjustment / repair to almost all of them at one time or another.