I'm Not Doing That

I have just been reading a news item about employees in certain organisations being asked to carry out various cleaning duties, such as cleaning their office desks or the toilets, as one of the consequences of the current virus precautions.  This seems to be causing quite a lot of controversy with staff objecting that "It's not in my job description"

That may be true, or not as most contracts when I was in full time employment added the requirement to undertake "other duties as requested by the employer".

I shall always remember the day (many, many years ago) when, arriving at the bank's office where I worked a dog had left a rather large, fresh deposit on the doorstep.  The manager told me to clean it up as I was the unfortunate who happened to arrive first.  I very reluctantly obeyed his request, retching and heaving all the time, but I never once thought to question his order, much as I would like to have refused.  

What is reasonable these days though?  Should employees refuse to do things they just don't fancy doing?