awk and regular expression

Ive got a file with words and also numbers.
Bla BLA
10 10
11 29
12 89
13 35

And i need to change "10,29,89,25" and also remove anything that contains actually words A-Z.
Got it this far:
awk '$2 > 0 {$2=20;}{print}' file

works good to change the second line to 20, however the answe is going into a DB so i need to remove "Bla and BLA from the outout, the answer.

I am guessing the answer should be something like:
awk '$2 > 0 && -ne [A-Z] {$2=20;}{print}' file

awk ' $2 ~ "^[0-9]+$" && $2 > 0 {$2=20;print} ' filename

This seems to work so far:

awk ' /[0-9]/ {print} ' file | awk '$2 > 0 {$2=20;}{print}'

However the file also contains words in the end of the file.
Bla BLA
10 11
11 25
12 30
13 25
Bla,bla,bla,bla,bla

Ouput now looks like this now:
10 20
11 20
12 20
13 20
Bla,bla,bla,bla,bla

But still got the last line to remove.

Thank you for the answer.
It seems to work but to the actually file....

I get no output at all to the actually file but if i do a file like the example it works..
The actually file looks like this:
"OL_ID OL_LINK_COST

----------- ------------

     51           10

     52           10

     53           10

     54           10

     55           10

     56           10

     57           10

     58           10

     59           10

     60           10

     61           10

     62           20

     63           10

     64           10

     65           10

     66           10

     67           10

     68           10

     69           10

     70           10

     71           10

     72           10

     73           10

     74           10

     75           10

     76           20

     77           10

     78           10

     93           20

     94           20

     95           20

     96           20

     97           20

     98           20

     99           20

    100           20

    101           10

    102           20

    103           20

    104           20

    105           20

    106           20

    107           20

    108           20

    109           20

    110           20

    111           20

    112           10

    113           20

    114           20

    126           10

    127           20

    128           10

    129           20

54 record(s) selected."

Thank you Anbu23
It helped me, alot!

awk ' $2 ~ "^[0-9]" && $2 > 0 {$2=20;print} ' file

This worked when i removed +$