Hot water, iso and salt, is a fine technique...
(I'd suggest following the iso/salt with a vinegar, to remove all salt and hard water residue, and then a last water rinse, should you go that route.)
However, I have heard that iso can remove labels...
Personally, I use and recommend 'Grunge Off'...
Another advantage to grunge off is that you can make a bottle last a really long time, since you can reuse it, by straining it;
(I keep it in couple squirt bottles, for easy use and to keep the cleaner stuff separate from the dirtier);
I'm still on the 2nd or 3rd bottle of the 6 pack we got 3 yrs ago.
Here's my process: I rinse a few times with super hot water, then squirt in a bit of grunge off, rinse a few times and it will be as clean as the day you got it.
Oh, and I use Q-tips and pipe cleaners for the small pieces, (hitters, downstems, etc.)
But yeah, I would also suggest using an ash catcher, they definitely help keep your tube cleaner, longer...
Clean whenever you need to "change" the water, and it will be a breeze.
...Cleanliness is next to G-dliness, as 'they' say.
Of course, I must admit, I have been uncharacteristically bad about keeping the glass clean recently, (since my op), I am so ashamed.
This will inspire me to get on top of that tomorrow! So thanks!!