Methods Of Bleaching Stains On Wood Floors
METHODS OF BLEACHING STAINS ON WOOD FLOORS
A. This procedure includes guidance on removing stains from
wood floors using different methods of bleaching. These
methods include using household chlorine bleach, oxalic
acid, or a concentrate hydrogen peroxide solution.
B. See 01100-07-S for general project guidelines to be
reviewed along with this procedure. These guidelines
cover the following sections:
1. Safety Precautions
2. Historic Structures Precautions
4. Quality Assurance
5. Delivery, Storage and Handling
6. Project/Site Conditions
7. Sequencing and Scheduling
8. General Protection (Surface and Surrounding)
These guidelines should be reviewed prior to performing
this procedure and should be followed, when applicable,
along with recommendations from the Regional Historic
Preservation Officer (RHPO).
NOTE: Chemical products are sometimes sold under a common
name. This usually means that the substance is not as pure as
the same chemical sold under its chemical name. The grade of
purity of common name substances, however, is usually adequate
for stain removal work, and these products should be purchased
when available, as they tend to be less expensive. Common
names are indicated below by an asterisk (*).
A. Denatured Alcohol:
1. Other chemical or common names include Methylated
2. Potential hazards: TOXIC AND FLAMMABLE.
3. Available from hardware store, paint store or
printer's supply distributor.
B. Mineral Spirits:
1. A petroleum distillate that is used especially as a
paint or varnish thinner.
2. Other chemical or common names include Benzine*
(not Benzene); Naphtha*; Petroleum spirits*;
3. Potential Hazards: TOXIC AND FLAMMABLE.
4. Safety Precautions:
a. AVOID REPEATED OR PROLONGED SKIN CONTACT.
b. ALWAYS wear rubber gloves when handling
c. If any chemical is splashed onto the skin,
wash immediately with soap and water.
5. Available from construction specialties
distributor, hardware store, paint store, or
printer's supply distributor.
C. Chlorine Bleach:
1. Other chemical or common names include Bleaching
solution*; Household bleach*; Laundry bleach*;
Sodium Hypochlorite*; Solution of chlorinated
2. Potential Hazards: CORROSIVE TO FLESH.
3. Available from chemical supply house, grocery store
or supermarket, hardware store or janitorial supply
D. Oxalic Acid (COOH)2 or (H2C2O4):
1. A poisonous strong acid that occurs in various
plants as oxalates and is used especially as a
bleaching or cleaning agent and in making dyes.
2. One of the strongest organic acids.
3. Other chemical or common names include Dibasic
acid; Ethanedioic acid; Acid of sugar*.
4. Potential Hazards: TOXIC; CORROSIVE TO CONCRETE,
STEEL, WOOD OR GLASS.
5. Available from chemical supply house, dry cleaning
supply distributor, drugstore or pharmaceutical
supply distributor, hardware store, or photographic
supply distributor (not camera shop). (Often sold
under a manufacturer's brand name; the chemical
name may appear on the label.)
E. Hydrogen Peroxide (H202): The concentrate solution used
for wood bleaching - typically sold as a two-part kit
containing sodium hydroxide.
1. An unstable compound used especially as an
oxidizing and bleaching agent, an antiseptic, and a
2. Other chemical or common names include Peroxide of
hydrogen*; Solution of hydrogen dioxide*;
Superoxol*; (hydrogen peroxide is commonly sold as
a 3% solution; Superoxol is a 30% solution;
Superoxol causes flesh burns; 3% hydrogen peroxide
does not). THIS PROCEDURE CALLS FOR USE OF THE 30%
3. Potential Hazards: TOXIC (when concentrated);
CORROSIVE TO FLESH; FLAMMABLE (in high
4. Available from chemical supply house, drugstore,
pharmaceutical supply distributor, or hardware
F. Clean, soft cloths
G. Clean, potable water
A. Glass or porcelain container
B. Stiff bristle brushes
A. Wash wood using denatured alcohol to remove any dirt or
other impurities from the surface.
B. Sand the wood and remove any paint or varnish. Brush
and/or vacuum dust and debris from the surface.
C. Remove any grease or oil from the surface by washing with
mineral spirits and a clean, soft cloth.
3.02 ERECTION, INSTALLATION, APPLICATION
CAUTION: DO NOT MIX AMMONIA WITH CHLORINE BLEACHES, A
POISONOUS GAS WILL RESULT! DO NOT USE BLEACH ON BIRD
NOTE: TEST CLEAN A SMALL AREA BEFORE PROCEEDING WITH THE WORK
TO DETERMINE THE BEST METHOD FOR REMOVING THE STAIN.
NOTE: TOTAL REMOVAL OF A STAIN MAY NOT ALWAYS BE POSSIBLE.
IN THESE CASES, LIGHTENING OF THE STAIN MUST SUFFICE. ON THE
CONTRARY, BE PREPARED FOR BLEACHED WOOD TO APPEAR LIKE-NEW IN
CONTRAST TO SURROUNDING WOOD THAT APPEARS MORE AGED.
NOTE: BLEACHES ARE WATER-BASED SOLUTIONS AND TEND TO RAISE
THE WOOD GRAIN WHEN APPLIED; THIS WILL REQUIRE SANDING UPON
A. Stain Removal Using Household Chlorine Bleach:
Recommended for removing an aniline dye finish and ink
stains from wood.
NOTE: BE SURE TO PROVIDE PLENTY OF VENTILATION; USE
CAUTION: DO NOT MIX CHLORINE BLEACH AND AMMONIA. THIS
WILL PRODUCE A TOXIC GAS.
1. Apply bleach to the stained area using a clean,
soft cloth or stiff bristle brush. Use straight
from the bottle; do not dilute.
2. Allow to sit on the surface for at least 10
minutes; reapply if necessary.
3. Thoroughly rinse the surface with clean, clear
4. Allow to dry for at least 24 hours before
B. Stain Removal Using Oxalic Acid: Recommended for
removing blue ink stains, iron stains and darkening or
blackening of wood due to age or previous cleaning.
NOTE: BEST TO USE IT WARM AND CONCENTRATED.
1. Dissolve crystals in hot water in a glass or
2. Apply the solution liberally to the surface using a
clean, soft cloth or stiff bristle brush.
3. Allow to sit on the surface for at least 10
minutes. It may take longer (up to an hour) to
achieve effective results depending on the type of
stain and type of wood; agitate with a stiff
bristle brush if necessary to aid in stain removal;
reapply if necessary.
4. Thoroughly rinse the surface with clean, clear
5. Allow to dry for at least 24 hours before
C. Stain Removal Using Concentrated Hydrogen Peroxide (30%):
Recommended for lightening woods or as a last attempt at
removing a stain before resorting to replacement.
NOTE: HYDROGEN PEROXIDE AT THIS CONCENTRATE IS THE
STRONGEST OF THE THREE BLEACHES LISTED. IT IS TYPICALLY
SOLD AS A TWO-PART KIT CONTAINING SODIUM HYDROXIDE.
1. Dampen the wood using a sponge soaked in clean,
2. Apply mixture of hydrogen peroxide and sodium
hydroxide uniformly over the surface. Follow
manufacturer's recommendations for application
procedures and dwell time.
END OF SECTION