The hood over my oven.

After using oven cleaner to wipe away a little of the sticky brownish-black residue, I now see there is a warning label. It advises me not to let grease build up here.

Funny.

What I don't understand are houses without any type of vent. Howinthehell do they cook?

Alas, that is me: the hood is not vented outside, don't ask me why.

As to how I cook... that's not the problem. The problem is how does anything stay clean? I have a vent in the ceiling so, at counter level, it isn't bad, but everything more than a shelf or two up is bagged (or just gets greasy).

I have an extractor that will run at commercial suction levels for 10 minutes (carries a warning so guess it is overtaxed if you use it longer than that. Told the sales outlet I wanted something that would suck a small animal up against the grille and hold it there (no hamsters were harmed in testing).

The only thing it doesn't work on is cooking foie gras - even on turbo super high setting, the smoke gets out into the hall and I end up getting a call from the alarm company asking if the house is on fire. (I once said "No, it is just the wife cooking again" but she heard and I suffered for it later). I have to work out some way to block the open passage with no door next to the stove for FG events. Maybe a half height old shower curtain velcroed to the sides...?

I have one question on vents - those kitchens with a cooktop in an island with a vent that rises up out of the island - do they really have enough suck to do the job?

Alas, that is me: the hood is not vented outside, don't ask me why.

I have been in at least two new houses with a cooktop in a counter not against a wall that had absolutely no vent of any kind--vented or not. One house had the cooktop directly under the master bedroom so there was no way to even install one. Wouldn't work for me. I cook several things that generate smoke.

Is it possible to install an outside vent in your case?

No, the kitchen is an interior room. The best I can imagine is to rip open the ceiling and attach the top of a new hood to the ceiling exhaust. Even this is still somewhat murky because I think the kitchen and both bathrooms share this same exhaust soffet, and I don't know that it vents outside, either. I could extend the soffet above another small dropped ceiling and into the walk-in closet from which it can find a window. But this is the sort of thing you do not do while you are still living here.

I can't imagine having a kitchen without an outside vent. Besides smoke, if you use a gas stove there is some carbon monoxide production- in a proper stove obviously not a lethal amount, or even enough to set off a CO2 detector, but there is some evidence that even mild buildup isn't great. Our hood has a reasonably powerful fan (600 cfm I think) but even when not doing something that will smoke I often run on the quiet setting when doing extended cooking.
I usually just soak filters in hot water and detergent, though I have run through dishwasher (by itself) on previous model.

I've only owned one low rise extractor - a Jennair range that had the intake between the elements, in the centre. I was lucky - we lived in a rather unconventional house at that point, with the kitchen/dining area four storeys up on 'stilts' on the side of a mountain. The range vented straight out through the floor and was quite effective in terms of suction power, but I expect that if it had to vent along a lengthier path, or into the same room, the results would have been less acceptable.

The one thing we did learn was not to apply light weight components to a pan with the extractor on full blast - you'd see the salt or whatever deviate from the pan and go right out the vent.