IMO chemspec make the best spotters/stain removers.
For the things like ink, grease, oil, make up, paint, chewing gum, sticky things etc citrus gel from Prochem does the job or P.O.G from chemspec or white spirit < within reason.
For browning, again Chemspecs Browning treatment works great.
For filtration marks you can try cirtus concentrate (restoremate), ultrapac renovate (prochem) or Enzall from chemspec does the job too.