The op is referring to TMV, or tobacco mosaic virus, which may be transmitted to treated plants via a tea/pest spray if the tobacco used was infected. The virus is incurable and requires the plants to be destroyed.

Leaves should never appear oily, only SLIGHTLY glossier than they had before. If they appear to be drying, you may have other problems, in which case you should post pics.

To minimize the risk of spreading TMV, if you make tobacco teas, use CHEAP CRAPPY cigarettes that have been heavily processed before packaging. Skip the all natural organic stuff. I recently had a discussion about this with a 2nd generation orchid breeder who confirmed that TMV is unlikely to be spread via processed cigs, but if he ever saw someone roll up in his greenhouse with a stogie, he'd flip!