I have two, one is a swandri and the other isn't but they're both 100% wool.
The one that isn't a Swandri has a label that says 'rinse in warm water, dry thoroughly, press with hot iron through damp cloth. Air thoroughly after washing and regularly after use'
The other one, which is a Swandri says 'shake clean, hand wash, max 40 degrees c, use approved wool detergent , do not bleach, do not spin, do not tumble dry, dry in shade, press with hot iron through cotton fabric'
HTH
I was told the reason it's best to avoid the plastic feel ones is because they can over heat the baby and cause them to sweat where as wool is breathable and won't alter their temp.