How to clean bronze

Bronze can­dle­sticks and fig­urines give the inte­ri­or a unique­ness and a spe­cial aro­ma of antiq­ui­ty. They can be extreme­ly beau­ti­ful, but they have one draw­back. Bronze objects under the influ­ence of mois­ture and air, as well as oth­er adverse fac­tors, are cov­ered with a blue-green coat­ing of oxides. This is espe­cial­ly true for things that were stored in base­ments or attics. Bronze items can be cleaned to restore their orig­i­nal look.
How to clean bronze

You will need

  • -sul­fu­ric acid;
  • -potas­si­um dichro­mate;
  • -ammo­nia;
  • -acetic acid;
  • -water;
  • - saw­dust;
  • - soda ash;
  • -pro­tec­tive glass­es;
  • -glass­ware;
  • -rub­ber gloves;
  • - woolen rag;
  • - wax or paraf­fin.


If the bronze has not oxi­dized too much and only a few spots on the sur­face need to be cleaned, use the fol­low­ing method. Degrease the item by rins­ing it in a warm soda ash solu­tion. Rinse with water.
Make a por­ridge with acetic acid and saw­dust. When the saw­dust swells, wipe the bronze object with the result­ing mass with a woolen rag. At the same time, acetic acid cor­rodes oxides, and saw­dust pol­ish­es the prod­uct. At the end of the treat­ment, rinse the item with cold water and dry thor­ough­ly.
In case of severe con­t­a­m­i­na­tion of the sur­face of the object with oxides, pre­pare the fol­low­ing com­po­si­tion. For 1 liter of water, take 10 g of potas­si­um dichro­mate and 20 ml of con­cen­trat­ed sul­fu­ric acid. Pour the solu­tion into a glass ves­sel not to the top (tak­ing into account the vol­ume of the object). Dip the object into the solu­tion and observe the process of dis­so­lu­tion of oxides.
As soon as areas of a clean met­al sur­face appear, imme­di­ate­ly remove the object and place it in a solu­tion of ammo­nia to neu­tral­ize the acid. After that, rinse the prod­uct with water and dry it thor­ough­ly. The process with sul­fu­ric acid and potas­si­um dichro­mate requires some care and skill in order not to dam­age the met­al.
After clean­ing the bronze, it is desir­able to wax its sur­face. This can be done with wax and a cloth, or with an alco­hol solu­tion of wax or paraf­fin. This treat­ment will pro­tect the sur­face of the object from oxi­da­tion.
You need to remem­ber the rules for work­ing with acid. In par­tic­u­lar, when prepar­ing solu­tions, it is nec­es­sary to pour acid into water, and not vice ver­sa.

A solu­tion of sul­fu­ric acid and potas­si­um dichro­mate is a very caus­tic and aggres­sive sub­stance. It can only be poured into glass ves­sels. Be sure to wear gloves and gog­gles when work­ing.

Help­ful advice
Potas­si­um dichro­mate can be pur­chased at chem­i­cal stores. Sul­fu­ric acid is also sup­plied in car deal­er­ships.