Restoring old harmonicas can be rewarding. Some of those old harps have a lot of soul!
Some Vintage Marine Band harmonicas are worth restoring because they have the potential to become responsive instruments with that earthy Marine Band sound.
But some are not.
Hohner went through a difficult time in the late 80s and early 90s and the quality of their harmonicas suffered. No matter how much work you do on such a harp, the result will be a serviceable harp at best. When they were first bought, a lot of them were hardly played because of the poor quality and they were simply put away. Today, these harps are surfacing on online markets as Vintage harmonicas in great "cosmetic" condition! They are cosmetically excellent because they have had barely any use due to their poor quality out-of-the-box.
How can you tell the difference between the good and the bad vintage Marine Bands? Here's a simple way. This method can help you spot a lemon over 90 per cent of the time.
Take a look at the back of the harp. Flip it upside down and look closely under the cover plate. How many nail heads can you see in between the reeds on the draw side (the bottom reed plate)? If you can see three, the harp is from a good period - either before or after the difficult time in the 1980s and 1990s.
If you can only see two nail heads, you have a harp that is most likely not going to be as playable as you would like it to be no matter how much work you do on it.