How do you remove mineral buildup in the skimmer line?

There is a white substance (kinda looks like caulk) encrusted in the pool pipe, right past the skimmer. Calcium maybe? There is that 90 degree angle so I can't touch it, but we used a small mirror to see. We poured a little muratic acid, and then vacuumed it out, but it just made it really white. My pool guys have no idea what it is. Is there any way to get rid of it with out replacing the whole skimmer? We bought a foreclosure, and this pool is old, this is our 2nd summer with the pool and the skimmer has never worked great. Please help so I don't have to pay $1200 for a new skimmer!