The other answers are technically correct that a separable-verb should be treated and translated as one word to obtain the correct meaning.
On the other hand for a verb to be separable usually means that it consists of a prefix and a (base) verb. Both do have a meaning of their own. Though simply translating them separately does not necessarily yield a usable translation. It can however convey a basic meaning, especially if one keeps in mind to also consider figurative meanings.
For your concrete example
abtragen consists of
tragen which translates to
to carry and the prefix
ab- which translates to
Separable verb prefix, from.
ab- + fahren (“to leave”) → abfahren (“to depart from”)
Separable verb prefix that indicates removal or quitting, off.
ab- + spülen (“to rinse, wash”) → abspülen (“to rinse off, wash off”)
Separable verb prefix that indicates a downward movement, down.
Separable verb prefix that indicates from or of.
As such the meaning of
abtragen can be understood as
to carry sth. away or perhaps
to reduce sth. [by carrying (some of) it away] here
to reduce could also convey a sense of a downward movement, e.g. making the pile smaller.
In combination with the context of
Schuld (which should probably be understood as some kind of
karmic debthere) a possible translation is
to pay of (karmic) debts.
For more information on separable-verbs see also link.