Hi Groyster, The only thing I do is gap them as necessary if there are any really leaky notes. The fact that they are a bit more airy than my other harps doesn't bother me too much as it is kinda part of 'the sound'
I have to say I that I really like that raspy sound you get with MB's which works well for blues and rock but they also sound good IMO on some of the sweeter melodies that I also enjoy playing.
I pulled some old mb1896s out due to the influences of mainly adam and deak harp and sent them out to harveyharp and MP tho they are older than methsulah they now play very well but understand they were a bitch to work with-I had given them up back in the 80s due to comb swelling
Nice one Groyster, glad to hear they were not past the point of recovery. I have no idea how long it will take before my MB combs will start swelling to the point of causing playing discomfort. I am not playing these harps exclusively though, so I might be alright for a while yet.