If you clean them and let them dry properly you should be fine to reuse - maybe try and keep certain syringes for certain flavours as they can leave a residual aroma. If and when you can though, I would totally recommend buying scales and measuring by weight - a lot less washing up lol
A tip to reduce that chemical note is to warm your batch in warm/hot ( not boiling ) water for around 15 mins. then shake it very well take the cap off and allow it to cool then replace cap shake well and steep this will reduce down the alcohol if the warmth of the water didn’t take it down then the atmosphere will do it. Steep them thou bc these batches that have those flavors are often harsh until they’ve fully steeped.
I was just mixing and idk why it didn’t occur to me when I read your post
but I’ve found fruity lemonade flavors are pretty good shake and vapes.
Plus they’re pretty much fully steeped after about 3 days
To do Shake n’ Vape with steeped flavors:
Why not mix up a 30ml bottle with only custard in it at about 10 - 20%?
Mix another bottle with some Bavarian cream or any cream and some yogurt or cheesecake. Steep those custards and creams at least one week. Then you can put some in your tank with some fruit concentrate and Diluter. Mixing to taste.
Diluter = Bottle with PG/VG/Nic only. And just a bit of sweetener if you like things sweet,
In the meantime, just take the 14ga needle off and use the syringe.
Also, every new flavor you get (and have), make a single flavor 20ml (or larger) test bottle.
Not only will you have it to test each flavor, but you will find some great single flavor vape.
You can also use them to mix on top of one another…on an RDA, or in a tank,which will teach you a lot about flavor pairing. [I think you just did that…I have no idea what those flavors are you have.]
I also suggest you at least use some masking tape for labels, so your writing doesn’t wear off the glass.