Just got my new triumph and couldn't be happier. After a range session there seems to be lots of fouling in the breach plug, using winchester shotgun primers. Should I just rinse with soap and water or is there a better way? Thanks.

This is not normal black powder or sub crud I have the same problem the first thing I found out was that Win 777 209 that they sell for muzzleloading is the wrong primer for this gun. The regular 209 win sells for reloading shot shells works just fine for me.
Cleaning, with the 777Win priner it just about closed off the touch hole in 10 or 12 shots I ended up running a drill the same size as the touch hole through to break it up to where I could do something with it the using # 9 smokeless powder bore cleaner gunscrubber and pipe cleaner to get it out. No more of those 777 Primer or Rem muzzle loader primers inmy gun they are way to dirty. Since I started using regular Win 209 in it soap and water and some pipe cleaners is all it takes.Lee

Soak in solvent, use a pick for the firing hole.

Just soak it in some Rusty Duck,run a drill bit in the flash hole channel,then dip it in the cleaner again. Ron