Personally i would not risk it for a biscuit no matter how little petrol is in the diesel from your misfuel.

It’ll be fine for an old diesel from say the early 90s or an old generator, but probably not worth it in a car unless you’re willing to pick up the bill for a new DPF.

5 hours ago, AF185 said:

I have an almost all diesel mixture from my petrol Fabia and was thinking of adding it gradually to my 2014 Diesel Honda CRV 1 gal to 1 tank. Will it be detrimental to the DPF or anything else?

Go for it, but see if you can detect any difference in engine sounds or behaviour. In the filling ratio you mention and with it starting out as 'mostly diesel' I can't see much risk at all.

I wouldn't chance it in a modern diesel that I cared about. Older diesels were normally ok with up to 25% petrol.

22 minutes ago, StevesTruck said:

I wouldn't chance it in a modern diesel that I cared about. Older diesels were normally ok with up to 25% petrol.

The handbook for my old SEAT Toledo 1.9SDI recommended adding a certain amount of petrol to the diesel (I forget the ratio) in the winter if you lived in colder climates.