Can you post back here which model you own? If you are not using a Hohner CX-12, then most other models of Hohner chromatics (and other brands like Huang, Yamaha, etc.) are the constructed roughly the same.

What you will most likely need to do is to take apart the 4 part mouthpiece section and clean all parts with an old toothbrush, warm water, and soap.

In the meantime, here's some more info:

Repair book- "Make Your Harmonica Work Better"-
http://www.harmonicastore.com/instruct_books.shtml

Website cleaning info-
http://www.angelfire.com/music/HarpOn/maintclean.html#cleaningtheslideassembly

Play on,
Dave Gage

I am playing a 10 hole Horner Chromonica 260 in the key of "G"
Thanks,
JohnM

You most likely need to take apart the mouthpiece section as I mentioned above and clean it. Check out the online source for the steps (or pick up the book). Take the time to note the way you take it apart and then re-assemble in reverse. It's very easy to do, but take your time the first time through. Let me know how it goes.

Cleaning the 4-part mouthpiece section is something that needs to be done every so often.

Play on,
Dave Gage

JohnM

The most important point is to work on a big surface so you don't lose any parts (especially the the 2 little plastic bumpers that are on the 2 screws that hold the 4-part mouthpiece section on) and take notes so that you can put it back together the way it was.

Tools needed:
Small flat head screwdriver
old toothbrush
soap and water

Parts to disassemble:
2 screws
2 little plastic bumpers
4-part mouthpiece section
(that's it)

Play on,
Dave Gage

I placed an order for the book and followed up your suggestion with the site reference Chromatic Harmonica Cleaning. One of the suggestions was simply to soak the chromatic with just enough water to cover the slide button and then dry it etc. Worked brilliantly!
This is the sort of practical advice we non practical men love and admire!
salut,
JohnM

I'm glad that worked for you. I personally would never recommend that procedure because if you screw up and get any water inside a chromatic you take the chance of ruining the windsaver valves and the cheap wood comb. As long as you're careful, that should be fine.

When the slide gets so bad that that trick won't work, then you will need to do a thorough cleaning of the slide and mouthpiece sections.

Play on,
Dave Gage