Each of these clues yields a two-word phrase wherein one word is a substring of the other. Specifically,
- Yarr, matey! As any good pirate knows, set aside a 10% share of your tech support for the church! (5,2) — TITHE IT
- The favored dessert of the dread pirate No-Lactose, it may be cold and fruity, but it be also shaped like our cannonballs! (6,3) — SORBET ORB
- All fields have their experts, be they gunners, deckhands, or navigators. This person be skilled at demonstratin' a theorem to be veracious. (5,3) — PROOF PRO
- I say, matey, steer clear of this grog made from Pacific salmon until you're 21. (4,7) — COHO ALCOHOL
- This be what you can find any good swabbie doin' in the aftermath of a fiery battle. (7,3) — WASHING ASH
- Episodes when that philanderin' paleontologist from New York City made appearances on shows that, unlike his main show, didn’t feature Central Perk. (4,10) — ROSS CROSSOVERS
- It be a performance involving a divisor of a number. (6,3) — FACTOR ACT
- Aye, for it be the act of thoroughly confusing Gene, who played Willy Wonka. (11,6) — BEWILDERING WILDER
- Ahoy! Methinks we can solve our rodent infestation by this act of gelding one. (10,3) — CASTRATING RAT
- What me laptop does whenever I make typos on me invoice. Avast! (11,5) — SPELLCHECKS CHECK
Removing one word from the other in each instance yields the clue phrase “The set of all wing covers for being casting spells”. This clues MAGE PLUMAGES, and iterating the above procedure yields the answer PLUS.