Bees are getting fewer and fewer for many reasons.  Check for a local beekeeper.  I am sure they will be happy to come and collect the bees.  I don't think any Africanized bees have made it up that far north, but be very careful around any bees that nest close to or in the ground.  If you must kill them, soapy water is probably the easiest way to do so.  They breath through tiny pores in their skin.  The soap bridges across the pores and they will suffocate.  They will all be on the hive early in the morning when it is cold.

You might consider putting them in your own hive.  Please destroy them only as a last resort.