Klean Kanteen bottles could not possibly be easier to clean. The interiors are smooth and threads are wide so there's no place for dirt to get trapped or for bacteria or mold to breed. The interior of the bottle is stainless steel with no liner to worry about so you don't have to worry about using a brush. Stainless steel doesn't absorb odors.If you research other sites including Klean Kanteen's site they will go into detail regarding which Klean Kanteens can be placed in the dishwasher and which should be hand washed.
Brushed Stainless non insulated bottles are dishwasher safe. Insulated bottles should be hand washed. Caps are dishwasher safe if there is no stainless steel in the interior of the cap. Painted bottles should be hand washed because placing them in the dishwasher may cause them to get chipped.
I suggest simplifying this question by telling you to just hand wash your Klean Kanteen. It takes 15 or 20 sec. and you don't have to think about it. You also don't have to worry about running the dishwasher when it's not full or forgetting to run it.
I put a drop of dish soap in the bottle and use a bottle brush. I use the same brush to clean the caps. Rinse the bottles and caps... place them top down in a dish drying rack so they drain and dry and you're good to go.
If you think you do smell some residual odor all you have to do is put a teaspoon of baking soda in the bottle, fill it with warm water, and let it sit over night. Put a teaspoon of baking soda in a cup of warm water and place caps in it and let them soak overnight. Clean the bottle and caps the regular way the next morning.
If you live in a high calcium area and you start to get so build-up inside your bottle put a tablespoon of vinegar in the bottle, fill it with warm water, and let it sit for an hour or two. Then use the baking soda method above to make sure you eliminate any trace of the odor of the vinegar.
I have been using Klean Kanteen insulated bottles for years and cleaning them each night takes no time at all. I haven't had to resort to the baking soda method or vinegar methods above.