I've just taken my washing off the line and noticed bat poo on some. Please tell me how I can remove this sticky poo.
Try a mixture of very hot water and peroxide with a brush
Since you have an outdoor area, I would suggest you wet the item, pour some of your liquid detergent or dish washing soap and let set for a few minutes, take a medium stiff brush (fingernail brush would work) and gently scrub the area to loosen the poo. Rinse thoroughly immediately and see if gunk is gone. If stained, spray with spot remover and wash in medium water so as not to set a stain.
Stain stick should work well.