Alternatively, live life on the wild side and don't use it~ You only really need it for your ID (which you can just write down and carry around), for swipe access or to prove you're a uni student. Granted, if you plan on getting MSA, that's where they normally put the MSA sticker.
The ID card is also used for:
1) Discount at Monash Sport.
2) Discount at many private sporting facilities.
3) Borrowing books from the library.
4) Used as a concession card in some foreign countries.
really useful for buying cheaper movie tickets
5) Discounted movie tickets
6) Heaps of other things (most on the line of discounts) that I can't think about.
Would suggest you get a replacement. Heaps of graduates still use their uni cards for concessions. Also if you want after hours access to the Eng comp-labs (if you're eng, or want to study in caufield library during swotvac, you'll need the card. Monash connect, Monash traffic (carpool) also requires your ID card.