They go in pens (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
inks
(Other definitions for inks that I've seen before include "Printers' media" , "Printing fluids" , "Liquids used for printing" , "Fluids from cuttlefish" , "Sink beneath writing fluids" .)
I believe the answer is:
inks
(Other definitions for inks that I've seen before include "Printers' media" , "Printing fluids" , "Liquids used for printing" , "Fluids from cuttlefish" , "Sink beneath writing fluids" .)