QUES: I am actively involved with our neighborhood citizens association

correct the punctuation.

CORRECTED: I am actively involved with our neighborhood citizens' association.

QUES: Channel magnets utilize a neodymium magnet and a steel channel

correct the punctuation.

CORRECTED: Channel magnets utilize a neodymium magnet and a steel channel.

QUES: The above offer is valid for max 10 rooms per day

correct the punctuation.

CORRECTED:
The above offer is valid for max. 10 rooms per day.