Wei T’o® Sprays stabilize works of art by neutralizing the acids that cause deterioration and prevent reacidification in future. These acids cause 80 to 90 percent of all paper deterioration. One treatment with Wei T’o® will protect paper up to 300 to 400 years by:


  • Neutralizing the existing acidity.
  • Impregnating an alkaline reserve to prevent future acid attack.
  • Protecting against oxidative attack.
  • Sanitizing the paper
  • Preventing the brown stains caused by fungi attack.


In terms of pH, each of the papers that you believe our society will need in 2050 should be deacidified if it has a pH below 7.0. The absolutely essential or high use papers with a pH below 8.0 should also be protected now.


Wei T’o® aerosol spray cans offer the best choice for an occasionally used, effective, and convenient spray. The additional costs of aerosol can manufacture and handling are balanced by the convenience and savings in set-up and take down time. Aerosol sprays make an extraordinary chemical solution, uniquely designed for preserving paper, available for use. Suggestions for spraying treatment procedure are:


  • Inspect work of art or document and prepare it for treatment. Begin by testing for sensitive and soluble inks, (Spray a little liquid into the spray can top, wet a clean, new “Q” tip with this liquid, touching unknown or questionable inks, colors, etc. in an unobtrusive spot. Look for any movement of ink, color, etc. both on the “Q” tip and on the paper. ( Don’t forget every color is a different ink or medium and, if unknown, must be tested.) The purpose of this test is to verify that neither the inks, medium, or colors, etc. contain materials that are soluble in Wei T’o® Spray.
  • Next, wet a new “Q” tip with distilled water and dampen each of the deacidified medium or ink, etc. test spots. Inspect for a change of color. The purpose of this test is to verify that neither the paper, if colored, or any of the materials used to make the image are sensitive to pH change. Sometimes artists or printers use materials that change to different colors like litmus paper does in acidic or alkaline conditions.
  • If you observed no changes, go on to the next step, i.e., remove dust and place the work of art upright on a spray board preparatory to deacidification.
  • Tilt actuator holding the spray can approximately six inches from the document, so the spray impacts at a right angle. Start spraying off the paper to clear the nozzle before treatment.
  • Wet the work of art thoroughly and evenly spraying from side to side in an overlapping pattern.
  • Lay the work of art flat to complete drying if a suction spray rack is not used.
  • If the document cockles, complete drying between sheets of dry blotting paper under moderate pressure.
  • After spraying is completed, remove the spray actuator and shake the can to keep the valve stem dry to prevent the gradual build-up of a blocking residue. If the actuator blocks, soak it in white vinegar to clear. Rinse in alcohol and blow dry before use.




Wei T’o® Spray No. 10 and Good News No. #111 are recommended as the most generally applicable Wei T’o® Spray for general use and for works of art. Nos. 11 and 111 have almost no ability to dissolve the soluble components in works of art and documents. All Wei T’o® Sprays have equivalent deacidifying power. i.e., potential to neutralize acids, and produce the same safe pH values. Each raises the same low hazard of causing the pH color shift explained above.


Wei T’o® Spray No. 11 (lowest vapor hazard of all Wei T’o® sprays) and Good News No. 125 offer improved penetrating power.


Wei T’o® Spray No. 12, being replaced with #125, is used for both general and special problems. e.g., penetration of acidic thick papers and boards, to which a previous person has mounted a work of art that has insufficient value to remove or restore; but yet deserves the protection a professional conservator can supply. Use No. 12 only on very stable inks, No. 111 on unstable inks.




All Wei T’o® Sprays are nonpoisonous, nonflammable and nonexplosive; Good News Sprays are flammable, and non poisonous. All should, nonetheless, be used in well-ventilated areas with the concentration of solvent vapors in workroom air kept within OSHA limits. The solvent vapors of Wei T’o® and Good News Sprays are considerably less hazardous than the vapors from rubbing alcohol. Material Safety Data Sheets are available on request from Wei T’o® Associates, 21750 Main Street, Unit 27, Matteson, IL 60443, or our web site at




  • Do not take chances. Test and prove your procedure before commencing the deacidification of valuable or unique items.
  • Always test unknown inks and papers before treating. Check both ink and paper for solubility and pH effects.
  • Always trigger the spray gun or aerosol can to double-check and clear it before commencing spray deacidification.
  • Contact Wei T’o® or your supplier for advice if difficulties are encountered. We want to share the treating procedures developed at Wei T’o® and the innovations our customers have taught us.
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