Grape scissors were used during the dessert (cheese or pudding) course of a dinner. After the grapes had been correctly cut, it was permissible for the diner to use his or her fingers.
The dining etiquette of the [Victorian/Edwardian] period encouraged the development of specific utensils for eating and serving particular foods such as grapes. ‘The Manners and Tone of Good Society’, first published in 1879, outlined the correct conduct of the dinner party but focused on the complicated and changing use of cutlery. With a few exceptions (such as for eating bread and some fruit), touching food with the fingers was frowned upon, and diners were presented with an alarming and growing range of specialist utensils for eating particular foods. It was important to be able to recognise items such as nut picks, sardine tongs and grape scissors, and to know how to use them correctly. The Manners and Tone of Good Society advised: “When eating grapes, the half closed hand should be placed to the lips and the stones and skins adroitly allowed to fall into the fingers and quickly placed on the side of the plate, the back of the hand concealing the manoeuvre from view.” Source: http://collections.vam.ac.uk