Unusual CERTO Bottle markings?

[kaatkins01]

I found this CERTO amber bottle. Usual embossed markings on bottle, however the base markings are odd. I recognize the Owens Illinois mark with a 6 to left of logo and a 3 to right of logo. Under the logo is a very large X with 6 below the X. I've read up on X makers mark but it is inconclusive, possibly an experimental bottle. Anyone seen this large X?

 

[CanadianBottles]

The X isn't a maker's mark, but I don't know what it is. Not sure why Certo would put an X on the base of their bottle.

 

[kaatkins01]

The X isn't a maker's mark, but I don't know what it is. Not sure why Certo would put an X on the base of their bottle.

Thank You

 

[J.R. Collector]

I found this CERTO amber bottle. Usual embossed markings on bottle, however the base markings are odd. I recognize the Owens Illinois mark with a 6 to left of logo and a 3 to right of logo. Under the logo is a very large X with 6 below the X. I've read up on X makers mark but it is inconclusive, possibly an experimental bottle. Anyone seen this large X?

This is all I could find doing a quick search. Hope it helps

 

[kaatkins01]

This is all I could find doing a quick search. Hope it helps

Thanks!