In the first episode of Peaky Blinders you find a scene where Grace Burgess personally applies for the job in the local bar/pub.
After discussing a bit with the owner whether she'll fit into this job or not, she starts to take up and empty pots from the floor into a bucket. The pots contain some 'mud-like' liquid. What was that and what was it good for? Did the bar visitors spit inside those pots, did they maybe urinate or puke inside?
The Garrison Tavern has ended up as a cross between an American speakeasy and a spit and sawdust British boozer. There is sawdust on the floor. As for the spit, a special recipe has been used to fill the metal spittoons at the foot of the bar, into which tobacco-chewing regulars would discharge.