For this type of "heat fixed" ink, any acidic fluid will work.

The CO can make human bodily fluids very acidic, potentially causing CO poisoning.

The oxidation of sulfides will generate highly acidic fluids rich in sulfuric acid that should suppress silica solubility.

And their death smelled vile: urine and blood and wasted guts and the sick smells of melted wing casings and acidic insect fluids.

The SII suit immediately vented the acidic fluid as his stomach spasmed.

Networks of tubules carrying free amino acids, chiefly lysine, and mildly acidic fluids, may act as primitive processing centers.

An acidic fluid burned Ryan's palate, and he spit several times to try to clear the bitter taste.

Enteric coatings based on CAP are resistant to acidic gastric fluids, but easily soluble in mildly basic medium of the intestine.

Burning in the throat - or hot, sour, acidic or salty-tasting fluid at the back of the throat.