I'm having some issues with my home mains power supply. Basically it's polluted. There's hum getting induced in every amp I plug in all sockets. Tired out various SS amps & Tube amps, there is always this slight 50hz hum which increases somewhat with volume control of the amps. The SS amps(practice/modelling combos) we tried exhibit it at a low degree, but the tube amps(30W combo/100W head) exhibit it a lot when you turn the master volume up while keeping the gain at zero. This all happens with or without a guitar plugged in, so its definitely not the guitar wiring.

Still waiting for the electrician to showup & get things checked. The house wiring is about 10yrs old, so that maybe a problem here.

But I wanted to know if there are specific devices that you guys know about that can filter dirty power. I guess these would be expensive, but I'd still want to know of the options for it.
10 years is practically new in house wiring terms. Might be a bad transformer outside, that's something the power company would have to take care of and probably won't.
I run my gear through a APC Power filter. Not sure if it does much since I don't have power issues. I got it more because it says on the label I can keep playing in a lightning storm. I thought that was WIN all of the way around. I also have a trex fuel tank Jr for my pedals and a Boss NS2.

Apc Av C Type 2 Outlet Wall Mount Power Filter, 120V

On a side note, I think most power cleaning/regulating is a scam.
I've been reading about power conditioning units the whole day. Most seem like glorified power strips with spike/surge protection. Not really convinced with the voltage regulation offered either.
^The APC unit seems like a good safety device incase of a power surge or like you said lightning strikes. I myself use a stabilizer with most of my electrically sensitive equipments.

^^Yeah I thought 10yrs was bit too early for house wiring to fail, but depends on the quality of the wire used too. I'm not sure what kind of quality/gauge wire was used during installation. Funny thing is that I live close to a power house/station, most of their equipment looks like its rusting haha

I found one way of fixing the issue by a device, expensive though. A true sine wave inverter seems to be the solution for providing a clean & constant voltage & current.
I won't be buying it though :P