I've read that hydrogen peroxide, perhaps Oxy-clean, and some of the bio-active enzyme and bacterial cultures used to treat biological spills can be used to clean clothing exposed to liquefied human.

Be careful with the bio-remediation agents as some are capable of digesting cellulose. Use the wrong type, at to high a concentration, for too long, and you could destroy your cotton and cotton blend clothing.

On one of my early jobs we used a commercial enzyme-bacterial brew that went by the name "Alive!" mix with warm water, let set for a time, and spray it on blood, sewage, liquefied crud draining from a dumpster, whatever. It liquefies the semi-solids, paper, eliminated the smell and dissolved many stains so they could be hosed or wet-vacuumed up.

Worked wonders on carpets fouled by domestic animals and post-crime cleanup where blood soaked the carpeting. Spray it on generously, let sit, wet vacuum up, repeat as needed. Use too much too long and it can dissolve the manila fiber backing. Allowing the carpet to loose dimensional stability and wrinkling. Whoops. No biggie; the carpet was toast anyway.

Peroxide and enzyme mixes are often better than the usual go-to agent, bleach. Pour bleach onto a large sewage spill and you get caustic chlorine gas mixed with the stifling pong of the sewage. Not the sort of thing most people were trying for. Bleach works fine on small spills.