Can you clean out an exhaust pipe?



I was wondering if anoyne has infomation or has ever cleaned out an exhaust pipe. Not the silencer, simply the pipe that comes directly off of the top - end. Thanks.
I was assuming that stuff builds up in an exhaust. I am trying to do anything to give my blaster a tune up.
A good way to do that is pour just a lil gas down in it an light a match let it burn the oil or you can dump gas in there an shake it around an get all of it out. But if you do it the second way be sure to let the pipe sit in the sun for a while to make sure it's completely dryed out.
That's why only a lil gas would be poured in, like mentioned before though why do that? the pipes get hot enough as is to burn the oil so there is really no need in doing it.
Now i have used the gas an match technique on a 4 stroke i had because my bike started smoking due to bad ring so i poured gas down it an light the pipe on fire to burn all the oil out.
tht is a pretty good trick, but i do not think someone should try it unless they know what they are doing.
CLR for the outside. Picture of its wonders.

Seafoam for the inside.
I like seeing people do stupid stuff like that because then when I do something stupid I dont feel so bad.
Lmao, people like that don't have any common sense, like hello to much gas in a almost closed in area is gonna create a prob, hahahaha