I just got a brand new keg. The keg isn't just new to me but totally unused. Do I need to use TSP to clean it prior to my first use? I'm worried about industrial residues that might be left on the stainless steel.
If you're at all worried, then I would clean it. It could be clear of all residues, depending on standards in the factory it was made in, or it could not be. The cost of cleaning it (in all senses, not just fiscally) is much lower than the cost of ruining a batch, or getting ill from ingesting the wrong thing. As cleaning and sanitation is most of what makes up brewing, I think it's always good advice to clean if you are ever uncertain.