Code:
alias stripbg {
  var %text = $1-
  var %i = $pos(%text,$chr(3),0)
  while (%i) {
    ;^ loop through all the ctrl-k's
    ;
    var %l = $pos(%text,$chr(3),%i)
    inc %l
    ;^ move to first character following ctrl-k
    ;
    if ($mid(%text,%l,1) isnum) {
      inc %l
      ;^ if its a number move past it
      ;
      if ($mid(%text,%l,1) isnum) { inc %l }
      ;^ possable second number, if so move past it
      ;
      if ($mid(%text,%l,1) == $chr(44)) {
        var %pre = %l
        inc %l
        ;^ if next character is a , then store that possition as everything before a potential background color, then move past it
        ;
        if ($mid(%text,%l,1) isnum) {
          inc %l
          ;^ if its a number move past it
          ;
          if ($mid(%text,%l,1) isnum) {
            inc %l
            ;^ possable second number, if so move past it
            ;
          }
          var %post = %l
          var %text = $+($left(%text,%pre),99,$mid(%text,%post))
          ;^ Therewas a background color and we have the position PREcedding it, and POST it so replace it with 99 being an invalid background color.
          ;
        }
      }
    }
    dec %i
    ;^ move to next ctrl-k
    ;
  }
  return %text
  ;^ return result
  ;
}


I cut that out from something else I had, and tested it, it appears to work, but might have a fault in it, if it doesnt dump a bg color one day, well sorry smile

I added the comments in here, incase someone couldnt follow (or wanted to)

Im sure a nice regex would matchup whats wanted with less if's but what the heck, i suck at regex so i didnt do one.