I find that there are some wasps flying around my house, and even built their honeycomb near the roof or soffit vent. Are there any methods to remove them or let these wasps leave? Thanks.
I've done this multiple times, all successfully: At night, when they're calm, take a plastic jar or cup (see-through is important) with a mouth as wide as the nest. Put a crumpled paper towel in the bottom. This will absorb shock so the nest remains intact. Bring some thin cardboard that can cover the jar opening.
With one hand, place the jar over the nest with the rim against the surface the nest is attached to. Scrape the nest off the surface by sliding the jar sideways, keeping the lid against the surface. Once the nest is detached. Bring in the cardboard in and slip it between the jar and the surface.
Now take the jar and cardboard as one and place them on the ground somewhere away from normal activity with the cardboard on the top. At this point I usually take a long broom handle or spray water to knock off the cardboard and then run inside. 😬
As Ed B. commented, by knocking down the nest, you'll convince the wasps to leave and build a new nest elsewhere. It's not necessary to spray -- at least from the point of view of getting them to leave! -- as they'll abandon a fallen nest. The difficulty comes in whacking the nest without getting a swarm attacking you. If you're fast :-) you can wait for a very cool night, hit the nest with a long pole, and run inside.
Otherwise, some spray to at least kill the exterior wasps and dissuade insiders from coming out a poisoned entrance should precede the knocking-down step.
Wasps can be dangerous especially if you are allergic so I would suggest hiring a professional exterminator because they have the right tools and safety gear to do the job properly. Wasps are very territorial and can sense danger so they will attack and sting. If the nest is near your home, just call a professional to do it for you. They will treat the area and also remove the nest for you to avoid secondary infestation.