The spillage bucket is just a easy way for the landlord to estimate waste, so he/she can factor the 'loss' into stock and accounting
I'm really suprised the number of people on here who seem to think it has some dubious other use.
( The magic of chutney Shakes it like an Instagram filter!, Fri 8 Jul 2011, 12:55, 2 replies)

I
believe that in some intitutions it's weighed and taken off the VAT bill.
(dchurch bah, Fri 8 Jul 2011, 13:18, closed)

I was sitting, rather drunkenly, at a bar chatting with the landlord about wastage once, and how they clean the taps every week by running a certain amount of booze through each one - I worked it out that cleaning the taps cost him in the region of £8-10k a year.

He almost cried.
( Hunter Stockton was murdered by a bicycle wielding axolotl,.,.,.,., Fri 8 Jul 2011, 14:17, closed)

I meantioned something similar in a previous post.
Most pubs nowadays don't seem to bother cleaning through with beer -- so you end up with the taste of cleaning fluid in the pipes for a while after they clean them. Unfortunately, I'm one of those people who, once I've tasted something, can pick up a trace ammount of it -- so I can't usually enjoy a pint nowadays.
(Me, I'm not... in any way intoxicated, Fri 8 Jul 2011, 17:57, closed)

I'd be inclined to agree with this
If it weren't for the specific instruction of "everything into the bucket except Guinness and cider."
(LongJohnBaldry, Fri 8 Jul 2011, 13:34, closed)