The short version
Cotton bibs hold wet against the skin and cause drool rash; muslin bibs dry fast and silicone pocket bibs handle solids. Large muslin squares are the most useful single baby purchase: swaddle, towel, burp cloth, sunshade and mat.
What happened
Someone gifted us a pack of twelve bibs. Twelve. Cotton, printed, with velcro at the back. I thought we were set. By month four, when the drool started, I understood: a cotton bib is a sponge you've tied to a baby. It soaked through in twenty minutes, sat wet against his neck, and by the end of the week he had a red, angry rash under his chin.
The drool rash taught me the rule for everything that touches baby skin: wet is the enemy. Dry the skin, change the wet thing, seal the skin. So the cotton bibs were swapped for muslin ones that dried fast, I kept a dry one in every room, and I started patting a thin layer of petroleum jelly under his chin at night. The rash was gone in four days.
Then came solids and the dal phase, and a whole new problem: not wet, but orange. Cotton bibs stained forever. The answer was a silicone bib with a pocket that caught the dropped bits, wiped clean under the tap, and never went near the washing machine. We had two. We needed two.
And through all of it, the muslin. I'd bought a three-pack of large muslin squares as swaddles. They became burp cloths, bath towels, a sunshade on the stroller, a cover for breastfeeding in the car, a mat for the floor at nani's, and once, in a hotel, a curtain. Three squares of thin cotton outperformed twelve bibs.
Dermatologists treat drool rash the way they treat any wet-skin irritation: keep the skin dry, change damp items promptly, clean gently with water, and seal with a barrier such as petroleum jelly or zinc oxide. The AAD's guidance for nappy rash applies the same principles.
American Academy of Dermatology, How to treat diaper rash. Source · Scripps Health, Baby drool rash: how to treat and prevent it. SourceThe verdicts
Large cotton muslin squares, pack of 3 (LuvLap, Haus & Kinder, Mom's Home)
Swaddle, towel, burp cloth, sunshade, mat. Dries in an hour on a Bengaluru balcony. The most-used thing we own.
Silicone bib with a catch pocket (LuvLap or similar)
For the solids phase. Rinse, dry, repeat. Buy two.
Muslin drool bibs, bandana style
For the teething months. Dry fast, don't sit wet on the neck. Four is enough.
The twelve-pack of printed cotton bibs
Sponges with velcro. They caused the rash they were meant to prevent. Regift them.
Product details are as we used them; the version on sale now may differ. Check the exact model and the manufacturer's instructions.