Most public facilities are closed in the UK due to the country's closure, but people are allowed to exercise and socialize outside, leading many to seek quiet public places if nature calls for a day.
"Disappointed to see so many discarded wipes on the Estate today. Alongside the trails and monuments. Please remember that there are no public restrooms open miles away at this time," wrote Balmoral staff.
"Part of the problem is that we are seeing a lot of non-biodegradable wipes being thrown away in the field," they added. "Also, people are choosing to relieve themselves right next to busy roads or monuments instead of walking a little way to avoid contamination."
But the castle recognized that people may need relief as they walk through the royal estate.
"If you need to urinate, do so at least 30 meters from lakes or streams," they added in a tweet on Sunday. "If you need to defecate, do so as far as possible from buildings, roads, waterways, and farm animals. Bury feces in a shallow pit and replace the grass."
The Queen and family members spend several weeks each year on the 50,000-acre estate in the Scottish Highlands.
She has spent most of the British confinement at another royal estate in Windsor, near London.