His castaway objects

Does "his castaway objects" refer to "second hand and thrown-away objects that Cary Liebowitz uses in his artworks" or does it mean "those objects of Gilligan's that survived with him after the storm"?

Context:

Cary Liebowitz may be the ‘Gilligan’ of contemporary art with his castaway objects. Like other artists who use second-hand objects and junk, Liebowitz exploits the cute and demonizes it at the same time, leaving the sentimentality in nostalgic and vintage ‘schlock’ for others to appreciate.