Identify poor quality products

[ferrisoxide]

This query:

select count(*) as count,  length(ltrim(gtin, '0')) as gtin_x, length(gtin) as gtin 
from products 
group by length(ltrim(gtin, '0')), length(gtin) 
order by length(ltrim(gtin, '0'));

returns:

count	gtin_x	gtin
1	0	1
1	1	14
1	3	3
1	4	5
1	4	14
7	5	14
3	6	8
76	6	14
1	7	8
1	7	14
6	8	8
9	8	13
163	8	14
143	9	13
3	9	14
1	10	10
1	10	11
777	10	13
14	10	14
3	11	11
14	11	12
325117	11	13
2474	11	14
34	12	12
267294	12	13
915	12	14
122288	13	13
2911	13	14
4	14	14
1	15	15
2	15	16
1	16	16

Clearly there is a lot of bad data in the production system (products with invalid GTNs). We need to figure out a plan for these records.