112:4 One is permitted to use paste to stick papers to a window, even within thirty days of Pesach, so long as the chometz in the paste is not visible. We are not strict on this because the paste is not entirely chometz, plus it is covered. If it is visible from the outside, it is forbidden. If done more than thirty days before Pesach, it is permitted in any case.
112:5 Ink that was prepared in alcohol before Pesach may be used for writing on chol hamoed because it was rendered unfit to feed even to a dog before Pesach. The same is true of all such things where the chometz was completely ruined for use as food before Pesach: one may keep them over Pesach and use them on Pesach. However, if a non-Jew prepared ink in alcohol on Pesach, a Jew may not use it because the chometz of a non-Jew is also forbidden for a Jew to use on Pesach.