Skin glue gobs up and sticks to base

Yes, Brandonee has it.  Get the old, dirty, globbed up glue off the skin with the paper bag (use sections about a foot long).  When the glue is warmed, pulling the paper off will take off the dirtiest old globs.  If you need to, use a metal scraper (not sharp) to get the remaining warmed glue off right away before it cools.  It will take a few times to remove all in one section if you wish to.  I usually leave some glue, then run my iron quickly over the remaining glue to smooth it out.  Get the Gold Label/Black Diamond glue in a can as it has a brush,  if you can only find the squeeze tube, use the metal scraper (cleaned) to spread and smooth it out.  Hang them carefully or leave them glue up on a table an let the glue dry for 12 hours or so before storing them till skiing on the mesh/plastic sheets.
OK, next..........NEVER SKI WITH DRY BASES!  Always keep an eye on that plastic.  After a day on granular hardpack you can see the "drier" area next to the edges under foot.  It is easy to see on black bases.  If the glue is sticking, or the bases look "dry", WAX them!  The old Tuas may have been summer stored dry, this causes the plastic to age (I've been told "oxidize).  NEVER STORE SKIS UNWAXED!!
Unless I'm skiing the next day, my skins go in the fridge for storage.  This is a must for long term storage.  The glue is formulated for cold, and warm storage will deteriorate its qualities.
n16ht5: Get all that glue off, renew with Gold Label, and good luck.

In the spring, the snow has needles and pollen all over it. This gets on the glue edges wherever they are not adhered well. If you do much spring/summer skiing, you may need to clean the skin glue frequently. Often, I just do a partial clean, tip and tail and some edges.

P.S. Waxed skis will turn better too!

Go to a ski shop and ask to grind the base, this will remove that sticky stuff. I have new skins, I think these have better glue.

After doing my own skins today, I'm adding:
I use the iron (same one I hot wax with - a small travelling iron) as hot as it goes, use the speed you move it to govern how hot the glue gets.
Look for the dark line along the very edge of your skin. That's the really dirty glue. Before I call the removal job complete, I lay the paper sack along 6 to 8" of the edge just overlapping by about 1/2" and concentrate heat there. If you can pull that dark line off with the paper, you have done a good job.
After ironing the glue to smooth it, wipe the hot glue off the iron with paper towel. When the iron is cool I remove the remaining stickiness with base cleaner. Speaking of which, base cleaner is an essential to good ski prep. It will remove the glue stuck to the base and clean off the pollen from Spring skiing. In late season, I always use cleaner before rewaxing.
Check the warning label on the skin glue, nasty stuff.
I may be a bit fussy about my skins but they go on and off about 2 to 300 times a season. I do a lot of all day tours and having them work that fifth or sixth time of the day to get me home is peace of mind.

That's impressive, probably one of the more tricky things to do, besides making a new pair of skis. Keep on truckin'