There's a bug at the end boss in the Trouble in Tuckborough skirmish.
First of all, this doesn't work if you go solo. Does in small fellow (didn't check full fellow or 12man).
Complete the skirmish normally until you reach the end boss (can do encounters if you like)
The end boss will spawn lieutenants thoughout the fight, leave at least 1 alive.
Then kill the boss and loot him (in battle). Then reset the last lieutenant (hips, feign death, die, whatever).
The lieutenant will walk a circle (evade him, easy) and dissapear. The boss will then respawn.
The boss drops over 200s per fellow member at level 65 skirmishes (done on small fellow) so that'll count up pretty quickly (the boss isn't that strong, just some lieuts he spawns can be a real pain).
So just repeat killing the boss like this and you'll get a lot of money along with a nice amount of guardmans (and other) marks (to trade for SM).
Have fun
