When Jon Pertwee reincarnated into Tom Baker in 1974, the Fourth Doctor of the popular sci-fi show Doctor Who ditched the foppish look of velvet jackets and frilly shirts, and went for the “Romantic adventurer” style, with floppy felt hat, long overcoats and, most iconically, his multicolored scarf.
Is it made of 100% wool? If so use wool wash and clean it in your sink following these instructions (I use a detergent brand called Soak for my hand knits).
Is it likely acrylic yarn? Put it in a mesh delicates bag, wash in your washing machine on a gentle/delicates cycle, and lay it out to air dry or dry in the dryer on low heat.
And if you’re not sure, any yarn can be washed using the hand wash instructions