I like the mug part of this tip. I would probably have dumped it in a bowl and regretted it!To easily remove the shells of hard or soft-boiled quail's eggs, cover them in vinegar and leave for 15 mins. Use a cheap vinegar! If you put them in a large mug you need less vinegar than a bowl. The vinegar literally dissolves and softens the shell and it slips off easily.
Anyone who has struggled peeling a quail's egg will appreciate this tip.