Another failure has inspired me to start this thread! Just tried heating dinner plates by keeping them in hot water..just got a slightly warm plate for the first few seconds, yet I always read this tip around Christmas time.
White vinegar and dish soap to attract and kill little black flies - nope
Bicarb of soda in boiling water to give extra crisp roasties - no discernible difference!
Getting a bit of eggshell out using a bigger piece - nope!