There’s a Unicode proposal for Textile Care instructions. This adds 40 new characters which represent instructions on how to wash your clothes. These are from ISO3758, which is the same as other international standards that can be used.
Much of this is based on work by GINETEX, an association for textile care labels in Europe, South America, Africa, and Asia. They’ve been working on care labels since the late 60s & pushing for regulation since the 70s. If a nation is part of GINETEX, they mandate that the washing care instructions follow correct use.
Unfortunately, many of the GINETEX symbols are trademarked, thus can’t be used freely in many European countries as part of the ISO3758 standard. This is partly because GINETEX wants to mandate the correct use of these symbols.
But, seriously, how do I wash my coat?