Were traces of cocaine found on ancient Egyptian mummies?

Question

Apparently traces of cocaine were found on Egyptian mummies. Given that the coca plant only grew in South America prior to Columbus, could this indicate the ancient Egyptians had contact with the New World, or is there a more rational explanation?

The discovery of tobacco fragments in the mummified body of Ramses II should have had a profound influence upon our whole understanding of the relationship between ancient Egypt and America but this piece of evidence was simply ignored. Then, sixteen years later, again quite by accident, more evidence emerged. In 1992, toxicologist, Dr. Svetla Balabanova of the Institute of Forensic Medicine in Ulm (Germany) tested the ancient Egyptian mummified remains of Henut-Tawy, Lady of the Two Lands. The results came as a "shock" to this scientist who regularly used the identical testing methods to convict people of drug consumption. She had not expected to find nicotine and cocaine in an ancient Egyptian mummy. New Dawn Magazine

Apparently Balabanova has published "First Identification of Drugs in Egyptian Mummies" available for a fee I can't justify paying.

A very similar story is echoed on other paranormal websites:

Such drugs come from the tobacco and coca plants respectively, plants that existed only in the Americas and were unknown before Columbus discovered America. To be sure, she requested that 3 other laboratories repeated the test and all came up with the same results. Even though these techniques are used in criminal lawsuits the world over and are 100% accurate, the scientific world, headed by the Oxford University, reacted furiously and denied the outcomes since it implicates that there was contact between Egypt and the Americas before Columbus, which is regarded as absolutely impossible. source

The story can also be found on an episode of weird or what available on youtube.

Of course, the fact that these claims circulate mainly on paranormalist websites is reason enough to be skeptical. It seems more likely that these results could be due to contamination, error, or possibly hoax. But if not....

Do these "cocaine mummies" indicate some pre-Columbian trans-oceanic contact between continents?

Answer 1

Trace amounts of nicotine, hashish and cocaine has indeed been found in many mummies.

A summary of possible reasons for why these mummies could show this can be found here, also with arguments against most of these possibilities.

A remaining possibility is contamination. The substances could have contaminated the mummy in modern times. Nicotine has for example been used as an insecticide. One study (Nerlich, A.G. et. al. 1995. Extensive pulmonary hemorrhage in an Egyptian mummy) did find different concentrations in different parts of the body, indicating that Cocain and Nicotine was ingested, while hashish had been smoked. But that is just one mummy.

Personally I find it hard to believe that almost every person who was mummified was also a user of cocaine or tobacco. If these was imported from South America in pre-columbian trade they must have been enormously expensive and fit only for kings.