Bedsheets & Linen
Blue Bins & Chutes
There are not many textile recyclers with a good reputation but these two are reliable.
Cloop Life Line Bins
Freecycle / Give Away
You can offer these through various channels. People usually only want sheets in very good condition but may be interested in an old sheet to use as a tarp for painting.
Singapore Really Really Free Market
Some animal shelters may take old bed sheets however they usually have enough supplies. Ask around to find out which shelter is currently in need.
Its Raining Raincoats
The Right to Live SG
Bedsheets & Linen in good condition are often collected in door-to-door collection drives and cash for trash events. Items that don't meet their quality standards may be rejected or sent for incineration.