Before opening our art gallery I was a bronze collector for more than 20 years and read much on the care and cleaning of bronze sculptures.  In additon, our company has been involved in several restoration projects of outdoor bronze statues that actually did need some work, but I can tell you that none of the materials included funky cleaning solutions or exotic oils.  However, before writing this piece I read several books on the topic including "The Care of Bronze Sculpture" by Patrick Kipper, which is available on www.Amazon.com.  Then, I spoke with several bronze artists to get their recommendations.  Finally, I spoke with two bronze foundry managers to get their feedback.  What I discovered is that there is a lot of misinformation out there and yes some dishonest dealers that would like to sell you additional cleaning products at outrageous markups.  So, I'm going to set the record straight and give you the straight scoop on the care and cleaning of bronze sculptures.

First, it is important to point out that bronze is a copper alloy (a metal created by the combination of other metals).  In the United States the minimum copper content for bronze is 90%.  In far-eastern countries such as Thailand and China, bronze has a copper content of between 60-70% and that is recycled copper from radiators, pipes, etc.  So, what I am going to describe here only applies to quality bronze sculptures and statues.

The very last step in creating a bronze sculpture is to apply a coat of wax.  This is usually done when the metal is still warm and allows for the wax to enter the pores of the bronze.  The wax acts as a barrier to the air and humidity that can cause the bronze to oxidize and turn green.  While that green look may appeal to some, others prefer to keep their sculptures looking new for as long as possible.

Unless the sculpture has been cleaned aggressively, the initial wax coating should last at least three months outdoors and probably much longer.  However,  differences in weather conditions can vary greatly, so a good rule of thumb is that if the water no longer beads up on the sculpture it is time to give it a cleaning and waxing.

The best cleaner for bronze sculptures (now get ready) is plain soap and water.  I read and was told several times that the best cleaner is just a little mild soap, like Ivory liquid dishwashing soap and water.  Just avoid any soaps with scents like lemon scent or other additives that might have unknown consequences.  Also, I was told that if you have water "issues" in your area you might like to use distilled bottled water.  But in most situation a hose or bucket of regular tap water is fine.  Just add enough soap to make bubbles in the water because all you really need to do is loosen the dirt from the surface. 

If you are cleaning an outdoor sculpture just add just enough soap to a bucket of water that it has some bubbles floating on top.  Too much soap could leave a soap residue that will require more rinsing later.  Then dampen a clean rag in the soapy water and wipe down the sculpture.  If the piece has a lot of nooks and crannies or bird droppings, a soft toothbrush might be useful.  I keep an old tooth brush in my cleaning supplies just for this purpose. 

I've seen some hack bronze sculpture dealers selling non-ionic cleaning solutions that are supposedly Ph balanced.  My experience in over 25 years of collecting bronze sculpture says that is completely unnecessary.  Think about it.  If you need to control the Ph of the water you clean the sculpture with what is the rain going to do to it.  Do you think the clouds test the Ph before raining on your sculpture?  If you need to Ph balance the cleaning solution for a bronze sculpture you might want to consider buying a higher quality sculpture.

Once the sculpture is clean, rinse out the rag and wipe down the sculpture with clear water to remove the soap residue.  Again, use the toothbrush with clear water to clean hard to reach areas.  If you have access to a hose near the sculpture this will work great to make sure the soap is completely removed. Next, allow the sculpture to dry completely.  This is very important because the next step is to re-wax the sculpture and you don't want to trap moisture under the wax coating.  Usually a sculpture is dry in a couple of hours. 

Once the sculpture is completely dry you are ready to begin waxing.  It is best to wax an outdoor sculpture in the heat of the day as this allows the wax to penetrate the pours of the sculpture resulting in a wax coating that will last longer.  The best type of wax to use is plain, clear, paste wax.  It usually comes in a can and is very inexpensive.  Avoid automotive waxes as they usually contain other cleaners, etc. that could be harmful to bronze.  But most importantly, car waxes tend to dry white, so if you leave any at all in little cracks or crevasses it will dry white and look terrible and you'll have to start all over again.  Although there are many good brands of wax, I'm going to discuss four.

Trewax Clear Paste Wax:  Trewax is a very hard carnauba wax, which is extracted from Brazilian Palm Trees.  One can should last you many years.  It comes highly recommended for its durability and versatility on light or dark patinas.  You can buy it online from Acme Hardware for $5.75 at the time of this writing. 

Johnson's Clear Paste Wax:  Good old Johnson's Clear Paste Wax also comes highly recommended.  Until I learned about Trewax, Johnson's was my wax of preference.  It is best used on darker patinas as it has been known to darken lighter colors.  It also produces a nice shine when buffed.  You can purchase it in most grocery stores for under $10.00 for a 1-pound can.  I just saw it online for $7.68 at USA Hardware.

Mohawk Blue Label Paste Wax: Blue Label Paste wax was recommended by several sources.  It is safe for most patinas and buffs out clean.  It is very difficult to find in a retail store, but I was able to find it online for $10.44 a can.  Click here for the web site. 

Renaissance Wax:  Renaissance Wax is the Cadillac of paste waxes.  It is a micro-crystalline wax polish that is manufactured in England and is used by museum curators around the word to protect bronze as well as swords and other metal artifacts.  It dries very hard and very quickly.  Most importantly it is resistant to fingerprints, which makes it ideal for a sculpture that is touched or handled. A small can runs around $15.00, but a little goes a long way.

For darker colored bronzes I would recommend Johnson's paste wax or Renaissance wax.  For lighter colors or multi-colored patinas I would recommend Trewax, Blue Label or Renaissance wax.   

To apply, use a soft rag or an unused paintbrush to get into nooks and crannies (I wrap masking tape near the end of the brush to make it a firmer at the end.  This makes it easer to get wax onto the brush.).  Apply a light coat and allow to dry.  Most waxes are dry within 20 minutes.  Then buff the sculpture using a soft cloth or clean shoe brush.  A second coat is recommended for outdoor sculptures.

So there you have it, care and cleaning of bronze sculpture demystified-soap and water and plain ordinary paste wax.  Notice there was no mention of magic cleaning potions or exotic oils.  In fact, everyone I spoke with strongly advised staying away from any type of oil whatsoever.  No fancy gadgets, just a clean rag, an old toothbrush and maybe a shoe brush for a high shine.

I can add one more thought to this for cleaning in-between waxing. Both foundries I contacted use liquid silicone (brand name Armor All) to clean sculptures before they are packaged for shipping.  It does not disturb the wax coating, adds another protective layer and leaves a nice shine.  I've been using it for about 3 years and I love it.  Now it even comes in convenient sponges and I can clean a life-size horse with one sponge.

I hope this helps.

Richard Rist, Owner