LIMIT WASHING AT ALL.
If you need to wash, hand wash in COLD water only, hang to dry. If you have a washing machine with a spin cycle, you can use the spin cycle to help spin as much water out of the clothing as possible after hand washing. Hang to dry.
Try to spot clean. If you must use soap, use a non-phosphate detergent. I use Foca Phosphate-Free Laundry Detergent.
CYANOTYPES ARE ARCHIVAL...
meaning they are meant to last for years (50-100+ years.) However, yellowing or fading may occur if prints are exposed to phosphates, high pH solutions, baking soda, washing soda, bleach, or alkalines. Sweat and hand oils may cause discoloration as well. They can also fade due to frequent washings/cleanings.
NEED A POP OF COLOR?
If you find yourself having to wash your item more frequently, soaking your jacket or item in cold water with a bit of hydrogen peroxide diluted in it can help bring a pop of life back into the print. Please wring out the water as much as possible and hang to dry.
SO... WHAT ARE CYANOTYPES?
Cyanotypes are one of the oldest photographic printing processes in the history of photography. Cyanotypes were first invented in 1842 by astronomer and scientist John Hershel (the son of William Hershel, the dude who discovered Uranus), not as a form of photography, but as a way to reproduce notes (blueprints). Cyanotype wasn't used as a form of photography until 1843, when botanist Anna Atkins used the cyanotype process to create a photographic album of algae specimens.
What's distinctive about cyanotype is its shade of cyan blue, which results from its exposure to UV light. A solution of ferric ammonium citrate and potassium ferricyanide is painted/brushed over an area, and then objects are placed over the brushed-on solution. Objects can be anything - plants, flowers, bottles, paperclips, scissors - literally anything that has shape and opacity to block the UV light! The solution is then exposed to UV light, and the result is ferric ferrocyanide aka Prussian Blue. After the print is exposed, the excess solution is rinsed away so that none of it remains on the print, and the print darkens to its final product.
The cyanotype chemicals I use to print my designs are non-toxic and do not present any health or safety concerns. All excess cyanotype solution is thoroughly washed out prior to drying, selling, and shipping out :)