Mug Press Attachments - bottles don't fit in press

[viksta87]

So i am new to mug printing.

I have a mug press and a flat bed press that i have to chop and change over when i want to use them, they are one of these multi press things (i have another flat press that i use for everything else)

I also brought a job lot of mugs and sports bottles from the same person, problem is that some of the mugs and all of the sports bottles don't fit. Is there a different attachment or some sort of insert i can get that will make them fit?