  I present a technique to remove the residual OH airglow emission from near
infrared spectra. Historically, the need to subtract out the strong and
variable OH airglow emission lines from 1-2.5um spectra has imposed severe
restrictions on observational strategy. For integral field spectroscopy, where
the field of view is limited, the standard technique is to observe blank sky
frames at regular intervals. However, even this does not usually provide
sufficient compensation if individual exposure times are longer than 2-3minutes
due to (1) changes in the absolute flux of the OH lines, (2) variations in flux
among the individual OH lines, and (3) effects of instrumental flexure which
can lead to `P-Cygni' type residuals. The data processing method presented here
takes all of these effects into account and serendipitously also improves
background subtraction between the OH lines. It allows one, in principle, to
use sky frames taken hours or days previously so that observations can be
performed in a quasi-stare mode. As a result, the observing efficiency (i.e.
fraction of time spent on a source) at the telescope can be dramatically
increased.
