c=1 does not work for Items

doesn't work

It works fine for me. Please describe the problem, don't just say it doesn't work.

c=1 is not "age", it's the count.
/kill @e[type=Item,c=1] kills one item
/kill @e[type=Item,c=2] kills two items
/kill @e[type=Item,c=3] kills three items
....
see http://minecraft.gamepedia.com/Command_Block#Arguments

It's both.
C=1 will select the oldest item
C=-1 will select the youngest item
C=0 will select all

Sorry run the command wrong works well