One side quest, "A Good Scrub," in *Kingdom Come: Deliverance 2* unlocks a series of bathhouse-related tasks, culminating in a search for a flea-infested item. Here's how to find it for Betty.
Pick Up ‘A Good Scrub’
Speak to the innkeeper in Kuttenberg about work. This leads you to Betty, whose bathhouse is in the southeast part of the city. Accept her offer to find Matsek in Grund. He's hesitant to be seen with the new bathhouse employees, so discreetly escort the three girls from the courtyard to the city with you.

Promote the Bathhouse
Help Betty advertise her bathhouse by shouting its merits at the grain market, horse market, vintners’ street, and merchants’ street. Remember, this needs to be done during the daytime.
Clean Up the Bathhouse and Finish ‘A Good Scrub’
Clean the bathhouse before the alderman's inspection. A timely cleanup is crucial to avoid closure and progress to the next quest, "Ill Repute."
Finding Fleas for ‘Ill Repute’ in Kingdom Come: Deliverance 2
After the inspection, speak to Betty about the bathhouse's remaining challenges. To influence the city council's decision on the main bathhouse, you must convince Councillor Naaz to leave the competing establishment.
Gather information from Meaty Mary, Katcha, and Little Lida to discover Naaz's preferences. You'll need chamomile brew for the wine cask on the second floor (Lida might require a noblewoman's dress as a bribe before revealing Naaz's fondness for fragrant oils). Alternatively, you can steal oils from a cabinet on the third floor.
Katcha mentions a past flea infestation. To find the flea-infested item, head to Kuttenberg's east gate. Search the beggars' camp there; a flea-infested blanket is your target.

Once obtained, return to the bathhouse and discreetly place the fleas in Councillor Naaz's laundry basket (and perhaps the clean laundry basket as well). Note that only one of the three tasks (the chamomile brew, the oils, or the fleas) needs completion to drive away the councillor.
Complete the quest and progress to further adventures, such as "Axe from the Lake."
Kingdom Come: Deliverance 2 is available now on PlayStation, Xbox, and PC.