I began using cedar oil last week and will convert all of my drawers over the next year. A friend has used it successfully for 10 years and convinced me to switch. I really dislike handling Vapona and was glad to find this safer alternative. I can post additional info if anyone is interested.
In the US, it's sold as "CedarCide PCO Choice" and is sold by Amazon. It comes in 1 quart bottles (just under 1 litre) for about $75.
To dilute it, I used my friend's directions. Use a jar with tight-fitting lid and add 500 ml water. Then add 15 ml of cedar oil; mix well. It will turn milky white and should last for years. It doesn't seem to settle, but I stir it each time I use it to be sure.
At a craft store, buy thin cork in sheets. Cut into pieces about 1x2 cm, skewer each piece with a pin, and position in drawer. Place 2 drops of solution on the cork. Repeat every 3-5 months; I plan to do it every 3 months to be safe. My friend has an alternate version: drop 10-15 drops of solution on a paper towel and place one atop each drawer. He says that it works just as well, but my cabinets don't have front doors, so I don't think it would work for me.
I asked whether he knows that it definitely kills parasites that may be present, not just deters them from entering the drawer, and he says yes...he has seen it kill them quickly. I don't know whether it has any effect on mould.
Thanks Danny for those useful info. I think the best idea to make sure it works is to try out on some not important drawers ( doubles for example or A- specimen ) and if there is no side effects on insects then introduce the method to all collection. As your friend use outside the drawers , we must make sure that inside we put enough or not too much of the solution . Also I want to try to introduce some ants or some sort of small insects and maybe mould as well inside empty wooden box and see if it has power to kill. Many years ago I used camphor oil inside drawers but it did not work properly as I had some pests in the past .
I will look forward to hear from you the resultes . Upon moving my collection to my final location I would love to drop use of chemicals as they smell tereble and also cause health hazard for long use.