PL/SQL :: Unescape Data Of Table Column Using Package Function

I'm trying to un-escape the data of a table column using the package function - UTL_URL.Unescape . But the problem is my column is a CLOB and length of my data exceeds that acceptable by the function.

So, i'm just trying to simulate that function behavior normally. My logic is to scan all characters with pattern '%yy' (HEX) and then convert it into DECIMAL using TO_CHAR(,'XX') . But got stuck in this regexp-replace.

with xx as(
select '<p>%3Cp%3Ewefwef%3C/p%3E</p>' col from dual
)
select
UTL_URL.unescape(col) x1,
regexp_replace(col,'%([a-zA-Z0-9]){2}','2|.') x2
from
[code].......