Hi Pigping and welcome.
Welcome to me too: I just joined and yours is the first post I've landed on.
As is often the case with almost everything in life, experts abound. In the end, I find that what works best for me is, well . . . best for me.
Regarding corncobs: to me they are throwaways, i.e., inexpensive pipes I smoke while working on my Harley, fishing, hunting, repairing my roof - you get the picture - they are subject to abuse. Filters - to me - are akin to those in cigarettes: they do little more than serve as a trap that accumulates stuff that eventually adds to or detracts from your smoke. What's the point of that? Rather than filtering, I keep a few cotton pipe cleaners handy and periodically run them down to the bowl as I am smoking.
Regarding trying tobacco in corncobs: like briar but more so, the corncob will, to some degree, flavor the smoke, especially so until the bowl builds up its char layer. If sampling tobaccos for their respective taste is your intent, the least intrusive vessel will be a meerschaum - because it adds little if anything to the smoke, which is one of the well-known attributes of a meerschaum. You can find relatively inexpensive meerschaums.
Regarding dedicated pipes, i.e., using a pipe for a specific tobacco: I am not an aficionado but I have been smoking pipes since 1967. I do not smoke "aromatic" tobaccos because you end up burning oils and/or sugars, which are what make aromatics aromatic (stick a match to a little pile of sugar and then smell the result). I smoke non-aromatic tobaccos, which are flavored, if you will, by curing them over smoke from a variety of sources. Aromatics, or their oils, tend to soak into the bowl or will be a component of the char layer. Thus, the pipe will retain some of the aromatic's flavor, which may contaminate the flavor of a different tobacco. So, yes, if you smoke aromatics and non-aromatics and, if you wish to render your smoke as pure as possible, then do not use the same pipe for smoking non-aromatics as you would for smoking aromatics. Even at that, smoking different aromatics in the same pipe will tend to contaminate the smoke from either, especially if the aromatic is strongly flavored.
Finally, it is a good idea to have a 2-3 pipes as a starter so that you allow a pipe to dry out between smokes. Aromatics, by the way, tend to be considerably moist compared to non-aromatics and do not dry out as readily - because of the added aromatic oils (therefore they also smoke wet - moisture collecting in the bowl and condensation in the stem). Therefore, aromatics may need a couple of days to dry out in the bowl. So, you could begin a pipe collection, if that is your goal, with a couple of very inexpensive pipes, and one quality pipe.
Since you mentioned washing the filter (which I would throw away) here is my routine for maintaining my pipes.
As mentioned above, I periodically run a cleaner through my pipe as I am smoking. How often depends on how hard I am puffing and how moist my tobacco is. (I keep bulk tobaccos in humidors at 70 degrees and 48-52% humidity so the moisture content is consistent). After my smoke is finished, I run a cleaner through the pipe and then let the pipe cool down. I then separate the stem from the pipe always turning in one direction (I attach and remove my stems always clockwise so I remember which direction), wipe off the ends of the stem and run a pipe cleaner through it. Cleaning the bowl depends on the design. First, remove the dottle - the left over loose tobacco/ash that remains in the bowl. It is important NOT TO DO THIS until the bowl has cooled. Generally, there are two designs of pipe bowls: those whose stem opens at the bottom of the bowl (most pipes) and those (like Peterson's) that open above the bottom of the bowl, which leaves a blind chamber beyond the opening to the bowl but isolated from the bowl itself. In other words, you have a main shaft that goes past the opening to the bowl with a side shaft from the main shaft into the bowl located above the bottom of the main shaft. This design creates a reservoir (the bottom of the main shaft) into which moisture will collect, ostensibly to prevent it from reaching your mouth. If you have a pipe designed as such (or one whose shaft was misdrilled) I find it effective to make a small roll of tissue, or wind 2-3 pipe cleaners together, or bend a cleaner in half doubling it and then ream/clean out any such trap. Finally, if there is a separate shaft into the bowl, run the cleaner though it. It is less likely but if you notice moisture in the bottom of the bowl after you remove the dottle, a wad of tissue or paper towels can remove it. Then stand your pipe upright and let it dry out for at least a day (I leave the stem off the bowl during the drying process thinking it allows the bowl to dry out more effectively and quicker, especially if the bowl has a reservoir).
This is probably a lot more than you are asking but I'm having the oil changed on my rocker so I had time to kill.
Enjoy.
Monk
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