Very mature rock

[Dearth]

So my current system has been up and running for close to 3 years and my rock is quite encrusted with all sorts of material from algae to coral to everything in between and I figure I have maybe 2 more good years out of the rock currently in my tank before the holes get covered by coral, detritus and algae. I have blown the rock I can reach with a turkey Baster but as I have a deep tank and way too much rock I cannot reach about half my rock without destroying the current habitat I have which I don't want to do at this time

My question is how do those of you with mature reef systems prolong the life of your rock?