From microfibre cloths to poly(vinyl alcohol) hydrogels – conservation cleaning of plastics heritage

•Cleaning tools were examined for their effectiveness at cleaning plastic surfaces.•Poly(vinyl alcohol)-based hydrogels were highly effective at removing carbon soil.•An innovative iodine-based technique was developed to detect residues of sebum soil.•Sebum soil proved more resistant to removal from plastics than carbonaceous soil.•PVA-based hydrogels induced noticeably less damage than traditional cleaning tools. In 2012, the EU 7th Framework Programme project Preservation of Plastic Artefacts in Museum Collections (POPART) used optical and scanning electron microscopies, as well as changes in surface energy and gloss to conduct an exhaustive evaluation of cleaning techniques for their effectiveness at cleaning cellulose acetate, polyethylene, poly(vinyl chloride), polystyrene and poly(methyl methacrylate). POPART concluded that applying anionic and nonionic detergent solutions with polyester microfibre cloth cleaned more effectively and produced fewer scratches than using dry, cleaning tools. Polyethylene and polystyrene were the plastics found to be most vulnerable to scratching. In 2018, the Horizon 2020 research project Nanomaterials for the Restoration of Works of Art (NANORESTART) evaluated the effectiveness of hydrogels for cleaning plastics and added infrared spectroscopy to the suite of evaluation instruments used in POPART. The present study compared on an equal basis the materials, model soils and most effective cleaning techniques examined by the POPART and NANORESTART projects. The research concluded that hydrogels induced significantly less damage than traditional cleaning tools and that sebum soil proved more resistant to removal from plastics than carbonaceous soil. [Display omitted]