There are several stretch routines shown in Eddie Bravo's "Mastering The Rubber Guard" book which should be a great help if you've not already seen them. I've been practising them every night for the last couple of weeks; I've already noticed an improvement in my range of movement (that last sentence sounds like an 80s rap. A bad one. Which I think is a good thing).
I'll never be as flexible as the likes of Eddie (especially as age and injuries are against me) but I've been pleasantly surprised by the change I've noticed even in such a short timescale. I also find the stretching really relaxes me at the end of the day, helps me wind down.