margin<-function(f,graphics=TRUE)
{
  mypath=getwd()
  str<-f@description$GUID
  str<-paste(str,"\n")
  cat(str)
  f.clean<-nmRemove(flow.frame = f,channels = c(1,2),neg = TRUE,talk=TRUE)

  if(graphics==TRUE)
  {
    
    par(xpd=FALSE)
    str<-f@description$GUID
    str<-gsub(".fcs","",str)
    str<-paste(mypath,str,"DensPlotClean.png",sep="/")
    png(file = str)
    plotDens(f.clean,c("FSC-A","SSC-A"))
    dev.off()
  }
 
  return(f.clean)
}