CLR it?
Could work, but it depends what it's clogged with. Depending on the faucet you/he has, the aerator can be super easy and cheap to replace. Some cost a little more because you might have to buy the whole sprayer nasal and just replace. Not all are made to come apart.
Also in my experience, when water to the whole building needs to be shut off for maintenance, when turned back on, dirt and other minerals get through the water system and your water will run brown for a little bit before turning clear. That's the dirt. So if that's the case then it might be slow just due to some dirt that needs to be rinsed off.
When I lived in Portland I thought the water was fine. No taste, nice and clear. But after a few years I checked one of my aerators just for the fuck of it, even though there was no pressure loss, and it was gunked up with some really nasty looking shit. Like thick dark earwax looking stuff. Now to be fair this was an aerator that was 7+ years old. Took a long time to build that up, but afterwards I just had my company buy me a whole new kitchen faucet.