Over the years I have accumulated a number of handy tips, but this is one I like to shout about from the mountain top. Someone told me about this over ten years ago, and I have used it on dozens of occassions.
I was informed that Zip Lock baggies are sanitized from the factory. Because of this, you can put yeast into a brand new baggie and store it for several weeks. For instance, if you wanted to obtain yeast from a local microbrewery, all you would need to do is to open the baggie for the first time (after the brewer has sprayed his sanitizer around the dump valve), being careful to keep your fingers on the outside of the baggie. Fill it up, zip it and toss it into your cold storage. I always write the strain and date with a Sharpie pen before I fill it up. I prefer one gallon Zip Locks for this operation.
I also do this for yeast strains if I know I am going to want to use it again relatively shortly. If I used a glass carboy for primary, I rack it to secondary and leave a couple of tablesppons of wort/beer behind. I swirl it around to get the yeast cake into a slurry, torch or wipe the opening with a vodka soaked papertowel, and lay the carboy on a low table. I do this because when tilting the carboy uoside it gets a little awkward if i by myself, and I use the table to stabilize the carboy. I just make sure the neck of the carboy does not touch the inside of the baggie at any time.
My friend Jeff Renner always ferments his primaries in a bucket to harvest (skim) the yeast in the krausen. And side-by-side experiements have shown that people prefered the brews made with subsequent batches using the top-croped yeast versus what settles on the bottom. However, if you prefer to use all glass for both primaries and secondaries, this is the way to go.