I like to have separate Blend files for each animation I do of my spaceship in a different surrounding. They are not linked together, but I have a file for each setting. Putting them all in one file would be too big. I do not use all the materials/textures/objects/meshes in each, though; I only use what I need. Unfortunately, the info is still there, making the Blend file huge, even if the model has a single, untextured plane.
How do I delete data sets from the file, such that no trace is left of it is left? This would trim the Blend file by a few megs, at the least.