Clarification:
1. OP Says don't use oils, but is referring to alcohol based tinctures as oils. If you use a tincture (fluid like what OP has described), there is a high chance that it is alcohol based in order to enter your bloodstream through your gums/lips. Most people when using the term OIL refer to distillates or vape juice, both of which would be perfectly safe to consume.
2. The Main thing to watch out for as others have mentioned, would be vitamin e acetate. However vitamin e acetate should not show up in any legally purchased THC or CBD product, and it is very unlikely that you would find it in your concentrates at all, unless you are purchasing specifically vape juice off of the street.
3. NOT TO MENTION: There are not very many legitimate vape products on the market for oil. Yes you can use your yocan aio, or your sai, but the best experience with oils is with a tank - something primarily only available from honeystick, yocan, and Crossing Tech.
I would also recommend making sure your atomizer does not contain cotton, as when using pure distillate you will only burn your cotton, and when using vape juice, you may have a reduced risk of burning cotton, but you will still gunk it up, and burn it much quicker than you could imagine. (Burning cotton, and other inhalant risks come from using coils that are not made of either ceramic, quartz, or titanium.) Keep in mind the type of wire you use should not matter unless you have a nickel allergy, but your wicking material will make a giant difference.
4. Another angle to consider would be the fact that lots of these illegal THC carts containing vitamin e acetate, were also spiked with other drugs, like coke, methamphetamine, and opiates. If you are making your own juice with "other drugs" the only advice I can give you is to purify your drugs, or purchase 100% pure pill base before you try making juice. DO NOT simply crush up pills and put it in your juice, the less amount of fillers you have the less your risk is. Some pill fillers could possibly contain vitamin e acetate or other chemicals that are JUST AS BAD for your lungs to vape on. Not to mention there is ZERO research about vaping anything other than nicotine or THC. So if you do decide to try doing that, I first of all recommend that you simply don't do it, you could get hurt. But if you decide to ignore me and do it anyway, just remember that there is still a large possibility that your health will be negatively impacted.
IN CONCLUSION (TLDR):
Tinctures with alcohol base are very bad for vaping
Traditionally referenced "Oils" such as distillate or hash (intended for smoking) are perfectly acceptable (and in some cases ideal) to vape on
VITAMIN E ACETATE is the key ingredient to watch out for, if you have any way to test your product for it, that will help you determine if your "oils" or whatever it may be, are not tainted or dangerous.
IF YOU USE ANY OTHER INGREDIENTS, the health risks are definitely there, vaping will not make your other drugs safer, it is not recommended, and if you must ignore my warning and do it anyway please use the purest possible base substance you can get your hands on in order to minimize any health risks.
Thank you for coming to my TED talk.