Yeah, I always thought that seemed like a stupid idea (and have never done it). By taking out the cartridge, blowing on it, and putting it back in again, you are in effect:

- Taking it out

- Performing a pointless ritual

- Putting it back in

In other words, you are re-seating it, which really does help. So just skip the blowing on it step and get the same results without corroding anything.

If there is actually some detritus on the contacts, clean it with some air duster or isopropanol on a cotton bud.