Sat Times Jumbo 852 Cryptic Explanations

[bergerhenn]

Help please, this weeks wasextra hard.
Why are the following answers?
1ac Prolong - Make last introduction to America, concealing name.(7)
10 ac Zinc - Metal's variable edge(4)
54 ac Yank - Eye a snake off and on, continually showingpluck(4)
18 ac a-e-s - Jumps up with bladeto cut flesh evenly(5)
Thanks and goodnight!

[octogenarian]

Prolog [ american for PROLOGUE ] + n =Prolong [to make last ]

[Jumbuck]

1a PROLONG [make last]

introduction to America = prolog (English spelling prologue)
name = n

10a ZINC [metal]

variable = z (maths)
edge = inch (as in moving slowly), not hard means remove the h (you forgot that bit)

54a YANK [pluck]

eye a snake off and on = eYeAsNaKe (i.e. every other letter)

18a AXELS [jumps up]

blade = axe
flesh evenly = fLeSh (i.e. every other letter again))

[tenflags]

Metal = Zinc variable=Z, edge= INCH, not hard means take the H off
Pluck = yank, off and on = eYe A sNaKe
jumps up = axels, blade to cut = axe, fLeSh evenly (every other letter)

[bergerhenn]

Thanks both of you . One more is 29 dn - ruled? -Were tops in football sort of light (5)

[Jumbuck]

RULED [were tops]

football = RU (rugby football)
sort of light = L.E.D.

[tenflags]

footall Rugby Union RU
sort of light LED

[tenflags]

sorry Jumbuck your answers wern't there when I satrted typing.. looks like I need a faster pc , connection or fingers.