This question is similar to Rules for affiliation for student doing unpaid research in his/her free time? and Is it acceptable to publish a paper using an affiliation with a former employer? except that I am a retiree.
I intend to submit a paper to a journal without mentioning any affiliation because I am no longer employeed. I have been thinking about a footnote in the paper indicating I am a retiree from my former employer for two reasons: I am receiving pension from the company pension fund and it is a well-known company in U.S. Using their name may make me look good. On the other hand, I feel like it's cheating because I am not their employee anymore.
Here's one approach: “(Ret.)”; subtle, direct, and in the literature (see 2):
1.Department of Earth Sciences University of Bristol, Bristol, UK
2.Global Volcanism Program, Smithsonian Institution (Ret.) Washington USA
3.USGS Cascades Volcano ObservatoryVancouver USA