Quoted from Buckman:Also read that about the Museum Putty (turbo20lbs mentioned it in Black_Rose's braggin' thread). Sounds like a good option.
I have been using this stuff for a long time works great if the figure is sitting pretty flush on where you are placing it. I currently have it holding down the Iceman Mod for XM and it is working very well. As mentioned above it is white so if you put too much or it's at a certain angle you will likely be able to see a small amount of white. One way to get around it is touch the visible edges of the putty up with a black paint pen before install then the white is gone.