Where the jar goes

Placement does half the work. A jar in the right spot outperforms two in the wrong one.

Four rules that apply everywhere

Air has to reach it. A jar in a closed cabinet only cleans the cabinet.
Closer to the source, not on top of it. A shelf near the litter box; not in the litter.
Waist height or lower in basements — cool damp air sinks.
Match size to space: 12–15 oz for ~450 sq ft, a gallon for up to 750.

Bathroom: Back of the tank or a shelf near the door; add a toilet spray for the moment itself.
Kitchen: Near — not over — the trash pull-out; away from the stove's heat.
Basement: A gallon at the foot of the stairs, a jar in the far corner.
Litter area: On a shelf within a few feet of the box, out of paw reach.
Closet: On the floor at the back, lid vented upward.
Car or RV: Crystals in a cupholder or console; secure the jar on the move.
Garage: On a shelf near the door where air moves when it opens.

Give any new jar a full week before judging it. The first days are always the quietest.