Swedging/Countersinking 
As clarinets age, the keys get loose from wear and dirt: metal is actually ground away at each end where it rubs against its post! Once the problem becomes severe enough, pads will no longer align properly with toneholes (causing leaks) and the whole instrument will have a loose ‘clackety’ feel.
Swedging, which is the technique used on keys with a through rod, is the process of compressing the metal at the end of the key to extend it and bring it back tight against the post. For solid keys that pivot on a screw, we countersink: slightly deepening the hole in the post until the point of the screw once again makes firm contact with the key and keeps it from shifting.
Properly done, it can restore an “almost new” feel to the mechanism, help eliminate leaks, and quiet the instrument.
Tonehole Frazing 
On older wood clarinets, toneholes suffer from a variety of problems. Years of adjustment and overhauls (especially careless ones) can leave small nicks and gouges around the rim of the toneholes, causing tiny leaks. It might not seem like a big deal, but multiply that by every tonehole on the clarinet…
As the instrument ages, it dries and shrinks: as it heats and cools, it flexes. A tonehole that was cut flat into a curved surface 50 or 80 years ago has often developed all kinds of minor warps which, when they meet a perfectly flat pad surface (if there is such a thing!) fail to contact evenly all the way around, causing yet more sealing issues.
The only way to effectively solve these problems is to re-cut the rim to its original contour. A special set of cutters is used to remove just a few thousandths of an inch of material, eliminating nicks and rendering the tonehole flat again, allowing for the best possible seal.
The Pads
I prefer to use Precision pads with double skin or tan kidskin. I also use pads of solid cork, which I bevel for each application. My personal preference is kidskin pads, with cork pads on the register key, the A, and the Ab. Sometimes I add them on F#, C#, side Bb and some trill keys. Why is this?
Well, cork pads have their pros and cons: they last forever, but they are noisier in operation. They make a great seal, but only on a clean flat tonehole. On a loose (unswedged) key, they are a positive liability. They are reflective because they are a harder material than felt, but can create an 'overbright' sound if used exclusively. Used on the register, A and Ab, they brighten the pesky throat tones. So, if I have a stuffy C# or a side Bb that doesn't speak as clearly as its LH equivalent, I use a cork pad as part of the voicing process. Who wants a dull note in the middle of a sparkling passage? Not you!
Spring Balancing
Uneven springing is a bit like walking around in only one shoe: it slows you down and affects your balance! By increasing or decreasing tension on individual springs, it is possible to make the instrument feel more 'even' overall and, hence, easier to play quickly and smoothly. Aside from evenness, it is possible to give the whole instrument a 'heavier' or 'lighter' feel, as the player prefers. Flabby and slow, or stiff and heavy, both come between you and the music!
Wetting and Clamping 
The Final step in a bladder pad job. I moisten each pad with a drop of water and clamp it overnight. The skin pulls tight as it dries and conforms itself more closely to the contour of the tonehole, leaving a ring visible on the pad. This gives not only a better seal but a more 'positive' crisp feel when the instrument is played.