Bristow has a very odd relationship with the office cleaners. Unlike his colleagues he delights in criticizing them, not just to others, but in direct correspondence (of course he never meets them because they only come in after normal office hours). Here is an early encounter
Our office cleaner doesn't put herself out
The wastepaper baskets are never emptied the floor is hardly ever swept
Last week I wrote clean me on my desktop before I went home
When I got in next day I found clean me yourself written there
We're now regular pen friends
Strip 30, April 1962.
The Cleaners attitude is to respond in kind. They complain about the mess in the Buying Department (though that's nothing compared to the Boardroom after a meeting of the Directors)and will often send Bristow little notes. These take the theme "Please put litter in the wastebasket where it belongs". "How true" Bristow responds as he rips up the note and chucks it in the bin.
Yet he is also pleased to receive some literary criticism
Listen to this
"Dear Mr Bristow.I have read your book Living death in the buying department. I suggest you brush up your descriptive passages
Polish up your vocabulary.. introduce some sweeping changes
and enclose the whole thing in a dust jacket"
It's from the cleaning lady
Strip 146, August 1962.
The cleaners of the Chester-Perry building are, of course, all female. Somewhat less usually, they do not appear to be managed by a man. They are a tough lot, capable of standing up for themselves. Witness their wrath when Sir Reginald is rash enough to pass some comments strip 10596. And yet the cleaners seem quite an intellectual bunch, spurning the cleaning in order to play
chess or bridge tournaments or knocking out passionate sex'n'violence
stories on the firm's word processors. It appears that much of the sex and violence is set on Bristow's desktop. 
This would be the same desktop that cleaners are wont to write long screeds in the dust starting "Dear Diary" or even love letters addressed to the firm's caretaker. Bristow has to dissaude Jones from examing the correspondence too closely - "It's rude to read someone's private letters".
Jones does not feel impelled to attack the quality of the cleaning, and enjoys a much better relationship. His laundry is done and buttons sewn on waistcoasts, stacked neatly away in his desk. But his trust is misplaced. He puts great energy into spring-cleaning one year, resulting in a visit from the editor of Desks and Surrounds, the clerical equivalent of Homes and Gardens. The editor wants to photograph Jones' desk for the next issue and (following a brief contretemps in which Bristow, as a self-appointed agent refuses to agree terms) they agree to do the shoot the next day. But it all goes horribly wrong strip 4627.