There is a second question about which I want to tap Sara's expertise here.

Almost all of us have from time to time had occasion to wash a rug or textile ourselves.

The advice usually given is to use cold water and some mild "unbuilt" detergent, like the Ivory Snow dishwashing formula or Orvus, a detergent widely used by rug dealers and collectors.

A few years ago, some questions were raised about Orvus and some have claimed that it leaves a residue and is acidic and therefore a danger to rugs long-term. Some Smithsonian researchers checked in to this debate with a letter to Hali, agreeing that Orvus often leaves residues and that these act like a transparent dye but they denied that Ovus is acidic or harmful and made favorable analogies with conditioners in hair shampoos.

Sara, since many of us will occasionally wash rugs ourselves in the future, what do you recommend in the way of detergents for cleaning?

Regards,

R. John Howe