Rosie, the old carpets used to be dumped. Any offcuts of carpet found in crew's cabins was purely coincidental

The system of crew cabin allocation was that, basically, new recruits (except those starting a more senior position) shared a 4-berth and it was unlikely that you'd get the same cabin back after crew leave. Most crew didn't bother to re-carpet these cabins. As you 'progressed up the ladder', it became more likely that you'd either get a 2-berth to share or a single berth to yourself (P. O's for example). Lots of these cabins were carpeted with... ahem... offcuts. Depending on your job/position onboard, it was likely that you'd return to 'your' cabin after any crew leave, so making it much more desirable to furnish it tastefully. One of the plumbers cabins on 6 - deck was all green... carpet, chair, counterpane/bedspread.
The main problem was with working boots getting so dirty and greasy. I used to keep my boots inside the cabin on a piece of cardboard but, inevitably, after a while, carpets did become grimy. I never left my work boots outside in case they went 'walkies' on their own
