This is an ideal job for the Internet Archive. The Internet Archive exists to preserve and make publicly available, digital texts, images, audio and video.
If you can scan your newsletters into PDF documents, you can upload them to the archive.
Anyone can create a free account and upload files. PDFs that are images of typed text will be character-recognized by Internet Archive and become searchable.
Be patient. Your document may not become fully viewable or searchable for some hours or days after upload if it is big.