Cleaning systems from Restorative Techniques were chosen for the internal cleaning, conservation and repair of St Mary's Church. The project was carried out over a two year period, with the work mainly focused on the cleaning of all internal stonework.

Thousands of annual visitors along with 75 years of candle burning had contributed to a high level of soot and dirt build up throughout the building. There were also areas of severe staining caused by water ingress from windows, gutters and roofs.

The majority of stone surfaces were simply cleaned by washing with water, but the sandstone and render vaulting within the church as well as some of the chapel altars and areas of limestone had suffered from more ingrained dirt and staining. Restorative Techniques' Latex Poultice Cleaner (weakest strength A) was used on these areas. The controlled method of cleaning, and stable non-hazardous waste product made this an efficient and effective cleaning method for these areas of the church.