The idea that workers shouldn't have chairs makes no sense. A rested employee is more productive.

"If you have time to lean you have time to clean" should be a rallying cry.

Change the discussion, clean everything.

You cleaned the glass an hour ago, clean it again. You cleaned the floor this morning, clean it in the afternoon too. The cost of cleaning supplies add up quickly if you can use up a month's worth of supplies in a week through constant cleaning. Use the most expensive disinfectants first. Make the place smell like bleach or ammonia.

Clean liberally and thoroughly. One spray isn't good enough, you need to get the gunk in the corners. You need to move signs to clean under them. You need to be in some corner of the store cleaning where you can't see customers.

Move everything off of shelves to clean into the very back. This will make the store into a disaster but you're cleaning.

When you're cleaning you can't drop everything help a customer, you have to go and put everything away for child safety and clean your hands. Don't want to get chemicals on what the customer is buying. Then go and get it back out and keep cleaning. Or you have to call a manager to help since you're in the middle of mopping.

Close down aisles with mopping. It's not safe to be there while the floor is wet so block customer access. You need to go above and beyond in the name of safety.

Show your employer that cleaning takes time away from making money and profit comes from down time. A store that has 100% use of its workers needs to hire more workers.

They'll have a very clean store and can see the cost of it.

If they give in at the very least they'll be remiss to ask everyone to clean constantly.