People often wonder what they should do with their dinner napkin when they momentarily excuse themselves from the table. Some wonder whether or not there's a right time to take the napkin from the table and put it in their lap. Others aren't sure where the napkin goes after a meal. On the chair? The plate? The basics of dinner napkin etiquette are agreed upon by most etiquette experts; the only differences tend to be situation-dependent.
Before a meal, napkins are most often placed on each plate in formal place settings. The simplest folds (folded into a flat square or a rectangle) are usually used in the most formal dining situations. Napkins might also be folded into three-dimensional standing shapes and placed on plates; less frequently, dinner napkins are rolled and then folded in half, placed in an empty water glass. In informal place settings, the napkin is folded in half or quarters (if it's large) and placed just to the left of the plate. Sometimes utensils are wrapped inside the napkin and placed to the left of the plate.
In an informal situation, napkins should be unfolded and placed on the diner's lap just after sitting down to the table. The same is true for formal restaurant dining, unless a waiter is unfolding and placing each diner's napkin on his or her lap. Even if a waiter is attending the table, a diner may unfold his own napkin at the same time and place it across his lap. In a formal, private dinner party, the napkin remains on the table until the hostess unfolds her napkin, at which time all guests should follow suit. If dining in an unusual setting, such as a spaghetti restaurant where the norm is to tuck napkins into shirt collars, eaters can follow the restaurant's standard or place napkins across laps as usual.
Leaving the Table
If a diner leaves the table in the middle of the meal, the napkin should be loosely folded (not crumpled) and placed to the left of the plate or on the chair's seat. Colleen Rush, author of "The Mere Mortal's Guide to Fine Dining," suggests that in formal dining situations the napkin is never put on the chair and always placed, loosely folded, to the left of the plate. In a restaurant, especially, napkins shouldn't be placed on an empty plate while temporarily away from the table; the waiter will have to move it should he need to set a dish down in the meantime.
Afterward, soiled napkins should be placed to the left of the plate, loosely folded. Placing it on the plate may soil it more than using it did, and placing a soiled napkin on a chair may soil the chair. At a formal dinner party, the hostess will place her napkin on the table to signal the end of the meal, and guests can do the same. If the napkin is especially soiled, it should be loosely folded, soiled side in, to protect other table linens.
Napkins should never be left on the table, even if they're paper and the meal is informal. Leaving a napkin sitting on the table suggests the eater doesn't have table manners. Using a napkin to clean off utensils is also an explicit don't, as is using a napkin to clean eyeglasses, fix make-up, or blow a nose. Napkins shouldn't serve as a place to deposit unwanted or disliked food, although if used to pick up food that's fallen on the floor, a fresh one should be requested.