Wearing a face covering is now compulsory in shops across Scotland.
People with certain medical conditions or disabilities, and children under five, will be exempt.
Face coverings are already mandatory on public transport including buses, trains, trams, planes and taxis.
The Scottish government has said it hopes using face coverings will provide an additional layer of protection to lower the risk of coronavirus being transmitted.
But it insists face coverings are not a substitute for other measures to stop the virus from spreading, such as physical distancing and hand washing.
'Take personal responsibility'
Police Scotland said it was asking people to "take personal responsibility to do the right thing".
It warned that it would enforce the law on face coverings but only as a last resort. In the first instance, anyone wishing to raise a concern should do so with shop staff.
ACC Gary Ritchie said: "We are asking people to take personal responsibility to do the right thing and remember the purpose of these measures is to aid the collective effort to stay safe, protect others and save lives by preventing the virus from spreading.
"Our officers will continue to engage with the public, explain the legislation and guidance and encourage compliance. We will use enforcement as a last resort only where there is a clear breach of the legislation.
"A number of exemptions exist that mean certain people are not required to wear a face covering in a shop.
"We would encourage people to raise any concerns with business owners or staff in the first instance."