I carry my coins around in that invisible purse - you know, the one with just a frame that snaps open and shut. Kidding of course, but I do almost always produce coins for a routine that way, whether it's for Matrix, or Silver Copper Brass transposition, or whatever. Holding the coins in finger p _ l _, and first displaying the purse frame between thumb and index finger, which allows for a Ramsey subtlety and the illusion of an empty hand, I then pour them into the spectator's hands, or onto the table. To spectators, that production is a great trick in and of itself, and it always gets a great reaction. And I like it better than just pulling coins out of a coin purse or my pocket. It's more magical.
Unless I am outside and it's hot, I generally like to wear some kind of jacket or other whenever I perform, because then i have an additional between 2 and 5 more pockets, depending on the jacket. That way, I can organize my coins and always know which pocket holds what. It also provides more options for ditching, sl _ _ v _ _ g, and/or cleaning up.