I got Pluid in one of my REOs that I've pretty much dedicated to absinthe flavors. However, truth be told, it's not the REO I dedicate to the flavor, but rather the combo of tubing, cap and bottle. I got 6 tubings, 4 caps and 30 bottles. When flavors are not particularly strong, I have a peculiar procedure for rinsing them out and getting all of the previous flavor completely out. It might sound crazy, but this is what I do.
1. Remove the bottle and dry the tubing with a paper towel. Remove any atty you have and blow through the connector to get any excess juice out of the tubing. If I could, I'd not reuse the bottle and just use a new one unless flavors are similar.
2. I usually have one bottle strictly for cleaning purposes. This bottle only sees vodka/hot water. Use that, fill it with vodka to the top, and screw it in. Shake it a bit and let it sit for at least 10 minutes upside down to get that tubing and cap soaked. Before removing the bottle, squonk it to get the inside of the tubing clean as well as the gasket/connector/drip well.
3. Remove the bottle, empty it and fill it with hot water. Screw it in and repeat what you did in step 2. You are mostly set.
(OPTIONAL)
For even less chances of the previous flavor sticking in, I do this which does cost me 1ml wasted of whatever juice you are planning to use. I also have another bottle for this purpose only but you can use whatever bottle you are going to use for the juice just remember to wash it with hot water afterwards.
4. Pour 1ml of the e-juice in a bottle and screw it in. Shake it a bit to get the outside of the tubing soaked, turn upside down to get the cap soaked as well. Lastly, squonk to get the inside of the tubing, gasket, connector and drip well soaked as well.
5. Remove the bottle. Blow excess juice and dry tubing with a paper towel. Those parts were now soaked in the new liquid, and will most likely not carry over the previous flavor you used at all. The main reason flavors get carried over is because the inside/outside of the tubing, gasket, connector and/or drip well still had traces of the previous juice and get mixed in with the new one. Following these steps I make sure that none of those parts has any trace of it and soaking it with the new juice before actually putting it on is just icing on the cake to seal the deal.
6. Fill a bottle up with your e-juice, screw it in and vape like a champ.
It sounds longer than it really is. But if a clear, true flavor is of much concern to you, I'd recommend something like that. While the tubing might still give off the smell of a previous juice if it was particularly strong, you can bet anything the actual flavor will be crisp clean. If you were vaping strong menthol, cinnamon, pluid or boba's bounty I'd still recommend just getting a set of tubing, cap and bottle just for those juices. Much easier, hassle free.
Your fingernails will leave little lines in the plastic, but I haven't had a bottle fail me yet. The only three flavors I've had trouble with are cinnamon, watermelon and pineapple.
