You were looking for something small, black and magnetic, then from Feb 2016 it was a 35mm film pot and then it became a tube under a "Guardian Gnome"!!! Alas this went missing in 2022/23 winter so the old hint "You'll know you're Gnome-and-dry when you spot the bag in the fairy light tree on the right hand side of entrance" is perhaps no longer helpful!
My grateful thanks to 
Bisnonno for doing some maintenance when the log roll was full. Many thanks John. And a BIG THANK YOU to fellow WBMC member Hilary Jones for putting the new nanocache I gave her into place in February 2015. I replaced this with a 35mm pot in February 2016 (in a nearby location as per the hint) as it seemed to have gone missing but this too went astray. I am therefore greatly indebted to VeerleD who very kindly placed another 35mm film canister in position in April 2017. I hope this one lasts a bit longer! Also many thanks indeed to Pompeyken for helping me keep this one going by replacing the log sheet in Dec 2016. A BIG THANKS also to The Cuthies & Max" from the West Midlands near me for putting in a new log sheet in a bag in September 2017. Also to gaidyz for adding a log in June 2018 All this help is much appreciated as I live far south of the border.
Most recently of all Meltdiceberg [:) & the Magna Defender put a new log & tube in place and I am very, very grateful to them for their help in keeping this one going. More recently Rietstal put in fresh logging paper when what was there previously seemed to have gone missing. Most recently of all my thanks to chramm_and_fam and TheCMHammond for adding a log and pot in August 2019 when the old log had gone missing yet again! Many thanks
And thanks to John (Bisnonno) Fish yet again in March 2023. I'm very grateful indeed.