When I tell friends and relatives how tricks are done, they really like it, and seem to get more pleasure out of it then being in a state of 'amazed ignorance'.
If I told them how the trick worked before I did the trick, that would be stooopid, because it would ruin the surprise for them of course, so I don't. After I do the trick, or someone else does a trick, and if they ask, and when I make sure they really want to know and this might ruin the 'magic' but they say it is OK, then I tell them. -They like to do the trick on others.
Most of them are about 95% there already with their possible explanations. I find that magicians telling the public that the public thinks everything is done with mirrors and invisible strings is insulting. If my friend asks if he can look at the deck, and this card trick involves an unexaminable deck, and I basically evade his request with patter or obviosuly swap decks, gee, I think he is almost there to figuring out the trick.
Same thing with an in half lady, finger choppers, levitations, a big thing disappearing, and so on, the more obvious tricks, and especially any gigantic stage illusions where the viewer obviosuly knows all the 'magic' takes place with the big apparatus that is on stage.
In the case of tricks due to skill, I usually show them the basics. Double lift, false shuffle, false cut, palm, etc., theory of various decks, mental effects, and then say that I or the magician is using 'some combination' of these to do the effect. I usually don't show them specifically because I don't have the skill to actually be more than a theoretician here. Moreover, they usually 'get it' without a start-to-finish demonstration.
In fact, there are many tricks involving skill that can be seen when viewed in slow motion.
There will never be a magic secret that can remain hidden after a thorough investigation.