Years ago a friend of mine was involved with a scheme to sort recyclables from waste using people with learning difficulties. The idea was that it would provide people who had little opportunity for conventional work to earn money and have the dignity of working for a living. But the scheme only worked financially with money from social services that would otherwise have been spent on supporting those individuals, hence the need to employ people who were otherwise unemployable. The scheme was a success in terms of its own objectives, but I thought at the time that it can't of done much for those involved, to be given an unpleasant job that those with choice in such matters avoid.

Maybe not a few days, but certainly several hours. When left for too longer thy tend to fall apart and dump dirt jelly like stuff into the bilge/engine tray, and that is a pain to clean out.