Allow me to share my experiences on the matter as I've had my share of resurrecting miniatures from terrible paintjobs.
First of all, instead of dettol, I use any brand of antiseptic gel. This one I get at a store with cleaning products for 5€ and it contains 600ml.

I've found out that dettol doesn't remove all kinds of paint. For most of it, it works like a charm, but I've come across cases that it doesn't do ANYTHING at all. This happens in cases like that:

The orc on the right cannot be restored using dettol. I don't know what kind of paint is this, it's very chalky, but dettol can't remove it.
However, the high mage on the left is a prime candidate to be dipped in dettol for some hours.
I understand that 24 hours is too many, usually I leave it a couple of hours, scrub some paint off, and dip it again for a few hours for the finishing brushing off.
For the cases that dettol doesn't work I use oven cleaner. This is a heavy product and it is unhealthy to breathe but works very fast.
I spray the figure, leave it 35-45 minutes (Friday movie reference) and toothbrush the poor bastard. Repeat once or twice if the figure has excessive paint. Only disadvantage of the oven cleaner is that it distorts the colour of the plastic. Example:

However, as I'm interested in painting the miniatures myself I'm not bothered by this disadvantage as the details are left unharmed.
One other thing about dettol is that it is having difficulties to work on a figure that has a proper primer. Most people that paint awfully don't use primer and that's why it's so easy for dettol to remove their paints. Same thing goes if the figure has varnish.
Anyway, my verdict is that dettol and oven cleaner are complementing each other and one is not substitute for the other. I use them both all the time and I can guarrantee that oven cleaner does NOT damage the figures' details in any way (at least my brand doesn't, it's called Mr. Muscle).