puny mobs suck! loot in them is really crappy. If you do plan to do this forget the iron man mission and head up to the gateway if the tp to there still works and hit the allophyl and other mobs near it that at least have skins and drop the L guns that have at least a little mark up...
or, better yet, do like I did recently and head to Rocktropia. Trolls are RTs version of puny but they have a major advantage in that their health is much smaller than a puny mobs health, so for same amount of ped in decay you get a hell of a lot more kills in, along with the 'kill bonus' on each of em.
Billy Bar is a noobie mission on RT that is great for this sort of thing since it's a repeatable instance in a tiny room where you kill about 20 or so trolls.
Trolls have 3 health. Puny have 10. Therefore you can kill 2-4 times more trolls for same amount of decay one puny will cost you depending on your weapon and now many crits you get.
Gloves may do too much damage on trolls though and give you overkill? I use a viper whip since it's really low damage, similar in level to the kiwio.
You'll probably never 'profit' a lot but if you count skill gains as a gain, trolls kick puny ass simply because of the number of kills you can get in the same amount of ped decay. Markup-wise though, the gateway might be better since those guns and attachments have high markup (even though selling them will likely be difficult since they are really low level and only have a few shots - better to use em yourself)