For the best effects, non-iodized table salt would be more desirable. Whatever kind of salt you use, try to dissolve it as much as possible to avoid scratching up your copper. Some aging compound recipes also like to add a 1/4 cup (. 19 liter) of lemon juice to the mixture. If you have lemon juice, use equal parts of all the ingredients listed above. [3] X Research source
Spray the copper lightly with the window cleaner again, but do not wipe it off this time. This serves to break the invisible surface tension so that the aging compound makes solid contact with the metal itself.
Don’t over-do it. It’s not necessary to soak the piece, so it’s dripping all over the place. Just use enough to wet it in an even coat.
If you live in an area with high humidity, or if you apply the mixture during a rainstorm, you do not need the plastic’s artificial environment. In general, it’s an advantage to try to age copper at the wettest or most humid point in the year, to give yourself the best natural benefit in the environment.
In general, you probably won’t want to age a piece using this method for too long, especially if you live in a humid climate. Remember that the copper will age naturally with time, as well, so you don’t have to do too much to get the effect you want on an object you’ll have for a long time.
