I'd like to take one of my old harmonicas and make it a comedy prop.
What do you suggest to saw it into 2 or 3 pieces.

I'm thinking it would be wise to cut the two outside silver (colored, I don't know the metal) pieces separately, while marking the 1 or 2 places to make the cut.
I'm thinking of thin magnets to hold the pieces to look whole.

I'm also thinking of making the cuts so the middle holes (4,5,6,7) are intact, so I could play a simple song. Maybe make it 3,4,5,6 if it was a blues run.

Any suggestions are appreciated.

A hacksaw might do the job.

If you can play it really well, just attach it to the back of a Jumbo Playing card.

Pull it out, show the card, put it up to the edge of the card and play a tune. The say, "It a playing card"!

Best harmonica gag ever...

https://www.youtube.com/watch?v=gIQkRYIi3fs

I do play it and feature it in comedy and with a couple of bands.
Been quite a while since I used the playing card gag.
What's old can be new.
How about with a debit card follow up
, with the line thus one is a PAYING card. Then a blues run.

http://youtu.be/nYI0SFsTarc

George Carl is still fun to watch.
A Swedish comedy magician does some bits based on Mr. Carl.

/


Another idea for the broken harmonica would look as if the harmonica was "tumbling down".

Talked to our shop teacher.

You are correct a Hacksaw will do the job with the right blade.

Will bring in an old harmonica to test it out.
Can't decide to go duct tape(silver) or magnets/flat to hold it together once cut.

Maybe disassemble it before cutting.

If you are thinking of making it a "break-away" harmonica, have someone punch you in the mouth (or arrange some other "accident), the two pieces of the harmonica go flying - or better yet cling together on a spring or something (no one knows what's inside those things). Then, after a pause, start spitting out your teeth (the old peppermint stick gag).

Chiclets comes to mind for the teeth gag.
Yes removing and cutting the outside silver covers is a great suggestion.