Q. Re- last question. If the glass with a mixture of vinegar or wine and a little liquid detergent, was placed before Shabbos and it was effective in attracting a number of flies. Can you now move it on Shabbos, or is it muktzah?

A. If there were already dead flies on the utensil at the onset of bein hashmoshos (twilight) of Shabbos, the vessel would likely become ”muktza machmas mius” (muktza due to repulsiveness – Shulchan Aruch O.H. 308: 34, 35), and you would not be able to move it for use at another location. However, Horav Shlomo Miller’s opinion is that if it is very repulsive and disgusting to the people close to it, one may remove the utensil out of the way, since it is considered as a “graf shel re’i” (potty or soiled diaper – ibid. and Mishna Berura 308: 130).

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a