I bought a used Turbonetics t4 about a weeks ago and I want to get it nice and clean before I install it. I was wondering if it would be safe to submerge the entire turbo into a bucket of kerosene and leave it for a day or so?

 

NO. You need to remove the housings and bead blast it to get under the oxidized iron, and perhaps even powder coat it. Please don't submerge that unit in kerosene.

 

I removed and cleaned the compressor housing and there was a lot of gunk in there, I hope the seals are okay. Is it necessary to do the same with the exhaust housing?

 

http://www.innotecworld.com/c-1064-turbo-clean-set.aspx
people have also used oven cleaner which has no problem removing carbon
there is a few products out there just for cleaning turbo's...go search