Why use disposable ink?

The typical ink or pigment that is used in tattoo process is kept
in a bottle, usually 1oz-8oz. The artist is supposed to open the
ink bottle, and fill the caps with ink prior to starting the tattoo.
The artist is not supposed to refill the same ink cap if it runs
out of ink during the tattoo process; for fear that the bottle may
touch some biohazard materials on the cap that is being filled.
New gloves have to be put on before the artist can touch the
ink bottle, and the entire work area has to be disposed of prior
to the ink cap being refilled. This is to prevent the bottle from
becoming cross-contaminated. This is a very big hassle, and is
seldom performed in the manner I just described. The ink shot
can be disposed of after it is used, and another ink shot can be
pulled out of the box with clean gloves without disposing of the
entire work area if the cap needs to be refilled. These are a little
more costly way of doing business, and not many brands of ink
are available in shots currently.