should I clean it?

[No4Mk1(T)]

Well speaking as a collector and shooter I'd say leave it as is. Put it back together and tuck it safely away. There are still thousands of affordable No4 rifles out there that have been fired. With the passage of time the few remaining unissued and unfired rifles grows smaller and smaller and the value both monetarily and to history grows. If given a choice a collector will almost always choose and pay a premium for the as new, unissued and unfired example. If you shoot it and your honest about it should you choose to shoot it that first shot is going to devalue the rifle by at least 25% and possibly more. No it's not all about money but you hold in your hands a time capsule so for me the "need" to shoot it wouldn't exist.