As has already been somewhat stated, if any of the coins have been handled with bare hands, they are going to be effected by the salt and body oil residue that gets transferred on to them (i.e. copper coins will eventually tone somewhat making fingerprints more and more visible with time, Zinc coated Steel Cents will eventually develop rust from the salt making it through the Zinc to the Steel or darker areas will develop in the Zinc due to chemical reaction). There are probably professional treatments for these but you will have to check with some of the top grading companies or coin professionals to if anything is available. In my opinion, you can do the best you can to mitigate any damage with what you have. You can neutralize most if not all of the damage from the salts and body oils by soaking the coins (not washing or rubbing as in cleaning) in a mild dishwashing liquid and water mixture, rinse in warm then cold water and pat dry between the soft folds of a towel. You then transfer the coins into a container containing alcohol, let soak for a minute or two, then remove, pat dry between the soft folds of a towel, then let them air dry for awhile. This should neutralize and/or remove most if not all of the harmful salts and body oils from the coins and they will be ready for 2x2'ing. Note: Even though you have removed the harmful salts and body oils from the coins to prevent any further damage, some damage has already been done and will show up on them eventually as fingerprints or smudges. Before you 2x2 the Steel Cents, it would be best to coat them with a light weight and clear oil such as Rem Oil or Watch Oil, pat them dry then 2x2 them. The oil should protect them somewhat from future damage due to the environment, hopefully prohibit rust from developing due to the salts and body oils that may have been on them previously from handling. Any yellowing from the oil should be fairly minimal but can happen over a long period of time. I would then find sealable glass containers (i.e. has a glass storage medium (round, square or rectangle) and a glass lid with a rubber type seal) and seal the coins up in them with a desiccant pack inside. I do not recommend using Zip Loc bags or plastic storage containers as the chemicals they are made of eventually breakdown and the chemical gases given off when they do so, can effect not on the 2x2 but also the coins since the 2x2's are not air tight.
Good luck! Also, I am an Error Coin Connoisseur and would love to see pics of the Steel Cent Error.
Frank
