I believe so, but acrylic bongs are generally used until they start getting funky, then they get thrown out. Acetone is what you need to be sure not to use.
I wouldn't. I remember cleaning my first acrylic bong years ago and the ISO washed off part of the colors from the plastic. The colors kept running for HOURS and millions of water rinses... I felt so sketched hitting that afterwards, hence why I got into glass at a young age. I wouldn't go with the acetone either. If you have to clean it I'd take the pressurized water blasting-off method OR the clean it with cloths, towels etc. Not that they're easy or all that efficient... Cheap plastic + solvents = cancer. Good Growing and Happy Toking! [edit:typo]
It will ruin it, don't do it. I've seen many threads where people did that exact same thing, only to ruin their bong. If you must do it, I would say it has to be very very very quick. Rinse it out FAST.
Almost boiling water with salt. Let it sit for a while, shake it up, scrub it with a toothbrush. Repeat with baking soda instead of salt to help get rid of the terrible smell they accumulate.
I use toluene to clean mine, it's a non polar solvent used in paint thinners I believe, it works by essentially dissolving a thin layer of the acrylic, It cleans wonderfully but will overtime make the bong thinner until eventually it eats a whole through it, also I rinse out with a billion liters of water afterwards.
I ruined two bongs this way. I'm pretty sure simple green will work. You can find it in the automotive dept. at meijer for like $5 per gallon. When I was living with my friends we used to keep a tupperware container filled with the stuff in our kitchen. Just toss your piece in over night and it was good as new the next day. In your case, plug the holes, fill your piece, and let it soak.
I use dishwashing soap, hot water, and a baby bottle brush. Then maybe every other month I hit it with Formula 420 for acrylics.