One of the attendees asked if practically one must have a unique clothing item designated for Shabos or can one wear clothes, such as a shirt, that he also wears during the week as long as it is laundered for Shabbos?

Rav Kook responded paskening that clothing that gets laundered regularly, such as shirts for example, can be worn on Shabbos after having be en laundered. There is no need to have unique shirts designated for Shabbos, just launder them for Shabbos. Clothing items that are not normally laundered regularly, such as tallis katan and a kipa, should be designated and unique for Shabbos.

Rav Kook mentioned that he himself saw this by Rev Elyashiv, his rebbi, and has been doing it himself since; Rav Elyashiv had a hanger with his Shabbos clothes prepared in the closet that held his Shabbos pants, tallis katan, kipa and a vest, all specifically designated for Shabbos. Rav Elyashiv did not have a shirt designated for Shabbos, but would change to a freshly laundered shirt before Shabbos.

According to Behadrei, since this psak was recently publicized there has been a run on kipas and tallis katan in the stiores as many people are running to get themsels new kipas and tallis katan that they would designate just for Shabbos use... When Rav Kook heard about this he gave his approval and said anyone who does thhings for the glory, the honor, of Shabbos will definitely receive the merit of the Shabbos providing protection for him and it will be a segula for protection, and will be given unlimited bounty (as promised in the gemara)....

Personally I have had a designated tallis katan for Shabbos for many years as an adult, for as long as I can remember. When I get a new tallis katan, I generally will rotate it in making the new one my "Shabbos tzitzis" and move my previous Shabbos tzitzis into my weekday lineup... I never had a special SHabbos kipa - maybe it is time to get one... back when I used to regularly wear a black hat, I did have a hat designated for Shabbos..