Heh.
somehow that method is not in the psych books
.
First I would want to know if he maybe lost something up there, or has a stuffed up nose or something medical?
Then if it is just a habit, here are some methods I have tried on kids (mostly when I taught, older kids, and not my own so not full time experience, only during class hours and had peer pressure too)
-make them wash their hands EVERY time you find them in the nose, most kids have better things to do with their day than spend it at the sink.
-Play up the grossness. NEVER use with a boy! (or not a typical boy anyway)
-refuse to have their hands on you, since they are snot or bugger covered, actually this wasn't a method or ploy it was plain and simple before kids I never had snot on myself and didn't want to start with theirs! EWWWW (only effective in k-5 and such when kids are still really huggy with teachers, or mine were anyway)
-make it a baby thing, (actually I used this with hands in the mouth, k-4 kids still do that alot), and I would emphasize the kids in school don't have hands in their mouths, and of course follow with a cool activity that only big kids get to do.
I have heard that ignoring works well, but knowing far to many adults who still pick their noses I don't trust it myself!
Oh and for fingers in the mouth with my two, I ask 'wheres your finger' and try to have several activities a day where both hands are needed (fingerp paint
.), and cut down or out all where no hands are actually needed (watching TV). Niether one has a major addiction though DS has his moments and DD is still getting teeth, so when they are bad, finger is in A LOT.
