Depending on just how bad it is then l would consider getting a professional cleaning company in. They will have a professional cleaning kit that might help you.

We find yearly inspections are a must regular texting too of tenants good idea also. Get a deep clean business in see what they suggest

Yes, thanks. My husband has visited at least once a year, and asked them to clean. They should have got it cleaned before they left, so I guess we'll be keeping at least some of the deposit to pay for that. Different cultures.

There are cleaning companies that specifically do deep cleans. Sadly it’s a common problem but yes, keep some of the deposit to pay for it.