Sliding window felt draught strip?

[Cruz]

Anyone got any suggestions on what I can use?

The window used to have one that had come loose, black and mouldy (I'm assuming that at some stage it was glued to one of the panes)

It broke into several pieces when I tried to remove it.

[Arvi]

i have a bit of similar strip off some caravan windows which looks exactly like the type used in windows of caravelles

i have some spare so you can have if you want