The unusual items were found among 2.8 tonnes of litter lifted during the Marine Conservation Society's (MCS) Big Beachwatch Weekend last year.
Scottish beach cleaners picked up 36,379 bits of litter on 45 beaches, a drop of 3% year on the amount collected in 2012. Chief among the finds was small pieces of plastic which have broken off larger items and could have been in the sea for decades.
But almost a third of all the debris collected came from litter left behind by people visiting beaches which had been dropped intentionally.
MCS Scotland programme manager Calum Duncan said: "It's simply being dumped and dropped, coming in from the sea, or being blown from the land. After 20 years of campaigning it's disheartening that in 2013, in the UK overall, we are seeing worse litter levels than ever."
According to the MCS data, 8.8% of the debris came from commercial recreational fishing stuff, including nets, weights and floats, while 7.4% was sewage-related.