If Oscar the Grouch gets Tzara'at on his garbage can, is that considered Tzara'at of clothing or Tzara'at of one's home?
It can't be tsara'at of a house, because round houses are not subject to tsara'at, as we read in mishna Nega'im 12:1.
כָּל הַבָּתִּים מִטַּמְּאִין בַּנְּגָעִים, חוּץ מִשֶּׁל נָכְרִים. הַלּוֹקֵחַ בָּתִּים מִן הַנָּכְרִים, יֵרָאוּ בַתְּחִלָּה. בַּיִת עָגֹל, בַּיִת טְרִיגוֹן, בַּיִת הַבָּנוּי בִּסְפִינָה אוֹ בְאַסְקַרְיָא, עַל אַרְבַּע קוֹרוֹת, אֵינוֹ מִטַּמֵּא בַנְּגָעִים. וְאִם הָיָה מְרֻבָּע, אֲפִלּוּ עַל אַרְבָּעָה עַמּוּדִים, מִטַּמֵּא:
All houses may contract negaim uncleanness, except those of non-Jews. If one bought houses from non-Jews, any it must be inspected as if they had then first appeared. A round house, a triangular house, or a house built on a ship, on a raft or on four beams, is not susceptible to negaim uncleanness. But if it was four-sided, even if it was built on four pillars, it is susceptible to uncleanness.
Additionally, only wool, linen, or leather clothing can contract tsara'at, as it says in Leviticus 13:47–48:
וְהַבֶּ֕גֶד כִּֽי־יִהְיֶ֥ה ב֖וֹ נֶ֣גַע צָרָ֑עַת בְּבֶ֣גֶד צֶ֔מֶר א֖וֹ בְּבֶ֥גֶד פִּשְׁתִּֽים׃ א֤וֹ בִֽשְׁתִי֙ א֣וֹ בְעֵ֔רֶב לַפִּשְׁתִּ֖ים וְלַצָּ֑מֶר א֣וֹ בְע֔וֹר א֖וֹ בְּכָל־מְלֶ֥אכֶת עֽוֹר׃
When an eruptive affection occurs in a cloth of wool or linen fabric, in the warp or in the woof of the linen or the wool, or in a skin or in anything made of skin
But we are assuming that there is tsara'at! So what's the solution? In fact, it is tsara'at of a house, and the trash can that we see is not the entire house. The trash can leads to a much larger house (it has contained a swimming pool, a bowling alley, ...), and we must assume that this house is indeed subject to tsara'at.