Yep, lemon glycerine swabs have been removed from our hospital. They smelled nice and were wet, but did nothing for cleaning or treatment of sore mouths. Some brands have alcohol in them which is drying.
Here is a quote from an article on oral care in the American Journal of Critical Care:
"Lemon and glycerine swabs stimulate production of saliva initially, but are acidic, causing irritation and decalcification of the teeth and rebound xerostomia." American Journal of Critical Care. 2004;13: 25-34
I think your text may be out of date on this issue. The normal saline solution sounds like the best answer to me, (it's isotonic, and won't sting like a salt water solution you would make in your own kitchen).
( p.s. After rinsing this patient's mouth, you better do a thorough oral assessment and notify the doc. Patient may need an antifunglal!)