What can I use to remove print from hard surfaces?
Tritan is a co-polyester. It is prone to stress cracking in the presence of a number of common solvents - cyclohexanone and tetrahydrofuran are used as surface bonding agents.

Acetone can induce stress cracking, as can IPA. 

I would suggest overprinting if you want to disguise the logo.

As for the aluminium item - take your choice - cyclo, THF, acetone, xylene - lots of options.