Polish Application Guidelines

All you need to know how to proceed with confirmation of citizenship procedure can be found here: https://www.gov.pl/web/usa-en/confirming-polish-citizenship-or-its-loss
Your ancestors could have lost Polish citizenship due to Article 11 of 1920 Law on Citizenship (in force till January 1951): http://www.refworld.org/pdfid/4fbf80ce102.pdf
Serving in a foreign army, being naturalized or holding a public office before 1951 could have resulted in loss of Polish citizenship.
This type of consular matter do not require personal appearance and can be conducted by correspondence.
All we need are either original supporting documents (to be returned to you) or notarized copies (by any locally available Public Notary). Certified copy when original is not available is acceptable.
Applicants residing permanently abroad shall submit an application form through the Consulate of the Republic of Poland competent with regard to the applicant’s place of residence.
Documents required:
1.       application for confirmation of Polish citizenship or its loss  filed out in Polish (filled out in Polish);
2.       relevant documents to establish if a person holds Polish citizenship (birth certificate, marriage certificate, certificate of baptism, old Polish passports, copies of parents’ or grandparents’ Polish documents, etc.);
3.       if there was a change to the name or surname, the applicant shall submit documents confirming this fact (marriage certificate, change of name);
4.       original of an ID (for viewing) or a certified photocopy of a current ID along with pages with official annotations;
5.       if applicants were born outside of the territory of Poland they are obliged to present an unabridged birth certificate containing the applicant’s parents’ names - along with its translation;
6.       vital records determining the applicant’s marital status (marriage certificate, divorce document or death certificate of a spouse);
7.       in some cases, a U.S. Certificate of Naturalization shall be submitted for viewing;

All foreign documents (not in Polish) have to be translated into Polish. If a translator do not have Polish credentials (a list maintained by Minister of Justice) and is just a local translator then it has to be certified by the consulate: https://www.gov.pl/web/usa-en/certifying-conformity-of-translations,  originals shown at the Consulate General of Poland in Houston (with regards to English only).
Be warned that this procedure may last several months.