Rabbit advice please?

I'm looking after my friends rabbit bertie, while shes away on holiday, i go next door early in a morning and let him out of his hutch.
This morning when i let him out i noticed that his back is very dirty and his fur is stuck together a little bit.
What i'm asking is should i clean it? brush it? or leave it? i don't think he can get to it himself.as you can tell i don't know alot about rabbits. he's very friendly and loves being fussed.

You say 'dirty' - is it poo?? Does it smell??

How tame is Bertie? Can you hold him still?

If possible, I would cut out as much as the gunk as possible, and use a comb to help you do it. Afterwards, use a wet wipe, or flannel with a tiny bit of shampoo (gentle shampoo....puppy perhaps?) to wipe over the areas.

It is fly season.... if he is left, flies will become attracted to his rear end and lay eggs. When the eggs hatch, they will begin to eat the rabbits alive, sometimes from the inside out without the owners knowing. It is a horrific and painful death which is best avoided.

If you can't do any of the above, then I would take him to the vets tomorrow (the owner paying of course).

However, if its just soil..... try and comb/use a flannel to get it out.

Hope this helps!

You need to remove as much of this as possible for fear of "fly strike" clippers work best but you need a steady hand, ring your vets they may suggest you take him in for sedation to be clipped off

Thanks for replying ladies.
It doesn't look like poo, just like wet soil, or mud before taking him to the vet i think i'l try some wet wipes and a comb, see how that goes.
Its not near his rear end it smack bang in the middle of his back.
thanks again.