ELCBK said
If it's not specifically an archival quality adhesive, you might consider some good adhesive used in garment/craft making that is reposition-able (cause you want to be able to take the chamois off to wash & not damage the wood). 
Aleene's Tack-It Over & Over - thick liquid that won't harm the wood, but will hold the chamois.
  

Yes, I'm familiar with the spray-can repositional adhesives from student-newspaper publishing, but spray might harm the violin, and also the Scotch stuff is three times the price of the European stuff which Amazon won't deliver to the UK. I'll check out Aleene to see if it's available here. AI tells me its pH value is 4.5, which is probably less harmful to wood than something caustic.

ELCBK said
The link I gave you is for a thick liquid, but a much less messy alternative is a thick, removable Acrylic Gel Tape adhesive, like THIS from Wotec.
  

Thanks. This seems to be the UK equivalent. I've just ordered a reel.

Initial results: - Chamois and Pritt stick are the winners.

Felt quickly got wet enough to dissolve the pritt stick glue. Wool feels dry even when it's quite wet. That's its advantage, but we do need dryness.

Chamois is more comfortable to the cheek and chin and so far it has stayed dry enough for the Pritt stick glue to hold, but the heatwave has abated.

Sellotape glue is usually highly water-soluble, so I haven't bothered trying it yet .

Back to shoulder rests. Simon Fischer mentions that the ideal is to go without, and lots do, including Yehudi Menuhin and Pierre, indeed had to before they were invented in the late 19th century. For me it's about comfort, not technique - I have a low pain threshold, and that wood pressing my collarbone is quite painful. When I look carefully at my setup with a Bon Musica I see that the edge of the violin does come within a hair's breadth of my collarbone, so I wonder if some kind of hardfoam strip around the back edge of the violin, thus not affecting the tone, is all that's needed. The problem, as ever, is how to fix it to the violin.

Or maybe it's just about finding the right place for that gel pad? There are one or two little pads you can buy, and I've got some (e.g. for my 'silent' EV), but decluttering means they are in boxes where only the underpants gnomes can find them.

I don't use practice mutes, but I do have quite a collection of orchestral mutes.

Currently on violin and viola I have Roth Sihons.

I had a copper-coloured Spector, which was my favourite (best combination of sound and speed of use and not vibrating or rattling and staying put), but, although I wasn't using it all the time, it quickly started to get loose on the bridge and didn't work properly. I diagnosed the problem, rightly or wrongy, as rubber being worn from the grooves by the D and A strings.

In case the brown rubber is softer than the black rubber, I just ordered a couple of black Spectors - and in case my Roth Sihons start doing nasty things to my string afterlengths.

The Shield mute with brass insert is OK, but not as rattle-free as the Stentor, unless I abuse the string windings, which I'm wary of doing. Simple tourtes are liable to rattle around too much.