Stains from Stargazer Lilies

[Aggypanthus]

On my new grey jumper. Been through a wash and not shifted. Anyone know how to gently remove without spoiling the jumper please ?

I once dropped a shirt onto a bunch of lillies, and it was COVERED in pollen - a couple of days hanging out in the sunshine did the trick. However, I did live in Australia at the time, and sunshine was not in short supply, unlike a grey British October...