To become rusty/ be covered with rust(rusting)
A layer of rust had accumulated on it. In the question: It had not been used and had deteriorated.
("A thread that is found full of rust or broken - is it pure, that all impurities are removed as soon as they are removed, and what? To the sea: Is it a thread from the beginning - a thread from the beginning, and now it is a rusty ladder (translation: This was before a good thread, and now it is a rusty ladder)!" - Nida 4:1, and also: "The room, the house, the house of the midrash...in the days of a storm And we ran away in anger between the walls of these fortresses, and there we will also return to destroy... the Jewish fire, that rust may not rise" - Bialik/ for the opening of the Hebrew University in Jerusalem, and so: "Koes began to be angry with the healers... in the meantime rust rose on his body and he sought to wash" - Agnon/ Tamol Shilshom, 217)
Translation
Expression (Hebrew)
הֶעֱלָה חֲלֻדָּה (הַעֲלָאַת חֲלֻדָּה)
Definition (Hebrew)
הִצְטַבְּרָה עָלָיו שִׁכְבַת חֲלוּדָה. בְּהַשְׁאָלָה: לֹא הָיָה בְּשִׁמּוּשׁ וְהִתְקַלְקֵל.
("מַחַט שֶׁנִּמְצֵאת מְלֵאָה חֲלֻדָּה אוֹ שְׁבוּרָה- טְהוֹרָה, שֶׁכָּל הַטֻּמְאוֹת כִּשְׁעַת מְצִיאָתָן וְאַמַּאי? לְיַמָּא: הַאי מֵעִקָּרָא- מַחַט מֵעֲלִיָּתָא הִיא, וְהַשְׁתָּא הוּא דְּהֶעֱלָה חֲלֻדָּה (תַּרְגּוּם: זוֹ לִפְנֵי כֵן מַחַט טוֹבָה, וְעַכְשָׁו הִיא הֶעֶלְתָה חֲלֻדָּה)!"- נִדָּה ד ע"א, וְכֵן:"הַחֶדֶר, הִשָּׁבֵה, בֵּית הַמִּדְרָשׁ...בִּימֵי סַעַר וְזַעַם נִמְלַטְנוּ אֶל בֵּין כָּתְלֵי הַמִּבְצָרִים הָאֵלֶּה וְשָׁם יָשַׁבְנוּ גַּם לָטַשְׁנוּ...אֶת הַמֹּחַ הַיְּהוּדִי, שֶׁלֹּא יַעֲלֶה חֲלֻדָּה"-בְּיָאלִיק/ לִפְתִיחַת הָאוּנִיבֶרְסִיטָה הָעִבְרִית בִּירוּשָׁלַיִם, וְכֵן:"הִתְחִיל כּוֹעֵס עַל הָרְפוּאוֹת...בְּתוֹךְ כָּךְ הֶעֱלָה גּוּפוֹ חֲלוּדָה וּבִקֵּשׁ לִרְחֹץ"- עַגְנוֹן/ תְּמוֹל שִׁלְשׁוֹם, 217)