Make sure your cleaning company has experience with cleaning stone. This is important because there are a number of solvents that can be used on stone which can't be used on other surfaces. If you want to gauge the experience of the company, then you can simply ask about past work or about the process it uses to clean stone.

Get local references for any company you consider hiring to do your stone cleaning. Local references will give you the best overall picture of how the company operates. They will also help you see the level of professionalism in the company before you spend any money. This can go a long way toward saving you money since it will stop you from spending money on unscrupulous or unprofessional companies.

Get an estimate from the company before you hire them. If possible, you want to have as many estimates from as many companies as possible. With multiple estimates, you will be more likely to get a good price for your stone cleaning. Also, the estimate will give you some leverage if your cleaning company starts to change the price on you.