Bicycle Mechanics - How do you clean the inside of a frame?

i have a five year old Giant MTB frame that i've stripped of all components. i've noticed there's a bit of gunk and mud etc on the inside walls. i got some of it out with water and washing up liquid.. but is there anyway to clean this tubing out properly?

thanks

I wanted to clean rust out of the seat tube. I wrapped a piece of sandpaper around a broom stick and used adhesive or double sided tape to keep the sandpaper in place. The sandpaper length equaled the stick diameter, or in other words, there was no overlap when the sandpaper was placed around the stick.

I could use that for the seat tube but there's mud in harder to reach places within the frame, like the short bar between the seatstays.. and the pannier attachment holes. i think i'd need some chemical to clear the muck out of there. any cleaners come to mind?

2500psi pressure washer?

too much hassle, the nearest one is 30 miles away.

if you have an air compressor try that, what we do in the shop is drop in some really good degreaser like simple green and let it sit then blast it out with water or whatever. then repeat until it is all gone.

For cleaning the accessible straight tubes like the seat tube or headtube, a 10 gauge shotgun barrel brush on a cleaning rod works well. For the less accessible tubes like the top tube and downtube, the same brush tied to a weighted string and pulled through does the job.

For truly inaccessible tubes like the stays and brake bridge, I have no better idea than the pressure washer recommended by Patrick. Then too, how did mud ever get into the brake bridge?

Note: edited to correct dreadful typos.

Shove a piece of Scotch-brite down the tube. If you want to get fancy with it, buy a dowel, split the end, and fasten the Scotch-brite in the split. Chuck the dowel into a hand drill and insert into the seat tube.

After all this cleaning, you'll most likely have bare steel tubing exposed. I'd recommend spraying something down there to prevent rust.

For the stays all you can do is squirt in water with a cleaner in it, let sit a few hours to a day and then blow out the goop with air pressure from one of the vent holes and let the goop come out the other. Repeat a couple of times and call it done. If there's still some in there then live with it. With the bigger tubes you MAY be able to drop in a handfull of barley to pea sized gravel and shake that around along with the water and soap to clean them. Just be sure that the gravel is of a size that passes easily into and out of the vent holes at one end or the other. A good source for graded size gravel of consistent size is an aquarium supply outlet. Another option, if you can find them in the UK, would be a handful of the steel BB's used with BB guns. Or a handful of the larger size steel shot used for reloading shot shells. Again both of these may be hard to find over there where the firearms laws are rather strict nowadays.

And a hearty ditto on spraying in some anti corrosion coating if the frame is steel.