Here are the skimming instructions from skim_mod:
  !! ====================================================================
  !!  Author: B. Jamieson
  !!  Date of Release: 31 Jan 2002
  !!  Last Altered: 9 Jul 2002 (BJ)
  !!                    Undocumented Changes 
  !!                16 Jan 2003 (BJ)  
  !!                    Add count of number skimmed to each channel. Add
  !!                    a second fill skim routine that caps skim at a
  !!                    specified number of events.
  !! --------------------------------------------------------------------
  !!  Description: Keep track of and update multiskimming channels.
  !!  This module contains two subroutines used to keep track of 
  !!  multiskimming channels.  ResetSkim is called at the begining
  !!  of dplot.f90 to resets the flags so that none of the skim channels 
  !!  will be written to unless FillSkim is called during the event.
  !!  
  !!  To set up multifile skimming follow these instructions:
  !!   1) From the o/s command line, set up environment variables 
  !!      with the names of the skim files you want to output to.
  !!      Up to 9 channels can be simultaneously written.
  !!       eg.  set up two files to skim to in linux csh:
  !!            csh> setenv SKIM1 "skim1.dat"
  !!            csh> setenv SKIM3 "skim3.dat"
  !!
  !!   2) Edit your .kcm file to tell MOFIA which channels to skim to:
  !!       eg. to write to the two files set up in 1), put the following
  !!           lines into your .kcm file (see multiskim.kcm):
  !!              skim/off
  !!              skim/on
  !!              ! Open the files for channels 1 and 3
  !!              skim/open 1 SKIM1
  !!              skim/open 3 SKIM3
  !!              ! Set up which YBOS event types to write to skim
  !!              skim/skip BEGIN_FILE
  !!              skim/skip END_FILE
  !!              skim/skip FILE
  !!              skim/write BEGIN_RUN
  !!              skim/skip END_RUN
  !!              skim/write EVENT
  !!              skim/write COMMENT
  !!              skim/write UNKNOWN
  !!              ! Enable skimming on channels 1 and 3
  !!              name skim skimoncode(1) = T
  !!              name skim skimoncode(3) = T
  !!              ! Show me which channels are enabled
  !!              show name skim
  !!
  !!   3) Put in calls to FillSkim, with the stream number to write to
  !!      as an argument somewhere in your code.  You will also need to 
  !!      add a module USE statement to USE skim_mod.  The code added 
  !!      might look something like this for skimming to the SKIM1 file:
  !!         !.
  !!         !. header code in your module is here
  !!         !.
  !!         USE skim_mod
  !!         !.
  !!         !. more type definitions, subroutines in module
  !!         !.
  !!         if ( This_is_what_I_want_in_SKIM1 ) then
  !!            call FillSkim(1)
  !!         end if
  !!         !.
  !!         !. the rest of your code
  !!         !.
  !! ====================================================================


Here are the skimming instructions to skim from classification:
  !! Once classifying is done, events can be selected for analysis, and or 
  !! skimming.  By default no skimming is done, and all events are 
  !! analyzed.  To select certain event types to analyze, select how the 
  !! classifying code results will be used by setting name Classify 
  !! SelectEvent to:
  !!   SelectEvent Value   Outcome
  !!   -----------------   -------
  !!      -1               Analyze events which were NOT
  !!                        selected by Classifying
  !!       0 (default)     Classify events, but analyze
  !!                        all events
  !!       1               Analyze events which were
  !!                        selected by Classifying
  !!   any other value     Don't run classifying code, 
  !!    (eg. 2)             analyze all events                      
  !! The type of event selected is set by setting one or more of the 
  !! following  namelist values to be true:
  !!   name Classify SelectSimpleClean  ! analyze only simple clean events     
  !!   name Classify SelectTimeClean    ! analyze only time clean events       
  !!   name Classify SelectOverlapDirty ! analyze only overlap events      
  !!   name Classify SelectComplexDirty ! analyze only complex dirty     
  !!   name Classify SelectBeamPositron ! analyze events with beam e+ 
  !!   name Classify SelectDelta        ! analyze events with deltas  
  !!
  !! Also, the type of events to skim can be independently selected by 
  !! setting all the skim namelists to set up skimming channels, and 
  !! setting one of the following namelist variables to true:
  !!   name skim SkimSimpleClean  ! skim simple clean events to channel 1
  !!   name skim SkimTimeClean    ! skim time clean events to channel 2
  !!   name skim SkimOverlapDirty ! skim overlap events to channel 3
  !!   name skim SkimComplexDirty ! skim complex dirty to channel 4
  !!   name skim SkimBeamPositron ! skim beam e+ to channel 5
  !!   name skim SkimDelta        ! skim deltas to channel 6
  !!

A newly added skimming feature is skimming of 100 events of different 
event types to user selectable channels.  To do this open the channels as 
per the instructions in skim_mod.  Then set the namelist variables:
name skim skimevtypetochan( EventTypeToSkim ) = ChannelToSkimTo
Where for EventTypeToSkim, and ChannelToSkimTo are numbers for the event 
type you want to skim to, and the file number you want that event type to 
go to.  I suppose if there is a demand for it, I could change the 100 
event limit to a user settable number... but that was all I wanted at the 
time.

Cheers,

Blair