half-empty cartridges still OK?

Don't worry about it -- just use the cartridges. If the ink appears to
stall, rinse the pen once and add some water to the cartridge and plug
it back in. If the ink was even halfway good when the cartridges were
new, this is the worst that could possibly happen.

Richard Pen wrote:
I found some old FP ink cartridges in a closed tin box and wish to use
them. About half the ink evaporated over the years. Are these cartridges
still useable?

Just make sure that you don't see any floating gobs of goo in there. I
found some old cartridges and I had to throw out the ones with the clots
in them. The others were fine.

N