25 Pa. Stat. § 3061
After the polls are closed and the last elector has voted in districts in which ballots are used, the election officers, clerks and overseers, if any, shall remain within the enclosed space. Before the ballot box is opened, the number of ballots issued to electors (at primaries the number issued to the electors of each party) and the number of ballots (at primaries the number of ballots of each party), if any, spoiled and returned by voters and cancelled, shall be announced to all present in the voting room, and entered on the general returns of votes cast at such primary or election. The election officers shall then compare the number of electors voting with the number of names marked as voting in the district register, "Voting Check List," and numbered lists of voters, shall announce the result, and shall enter on the general returns the number of electors who have voted, as shown by the "Voter's Check List." If any differences exist, they shall be reconciled, if possible, otherwise they shall be noted on the general returns. The district register, the "Voting Check List" and the numbered lists of voters , together with all unused ballots, and all spoiled and cancelled ballots, and all rejected voter's certificates shall then be placed in separate packages, containers or envelopes, and sealed, before the ballot box is opened.
25 P.S. § 3061