I used marine epoxy putty to raise my d,eb, and f left hand palm keys.
Really simple process...
1. remove keys, one at a time works best (see steps 6 and 7).
2. scuff off lacquer with sandpaper
3. break off and knead an inch to an inch and a half length of putty to activate the catalyst.
4. apply to key and shape as close as possible to key shape - make taller than you think it needs to be.
5. allow to harden.
6. lightly scuff/sand/shape hardened putty with sandpaper
7. replace key on instrument - check height and operation.
8. repeat steps 6 and 7 as needed to adjust the feel and eliminate contact with neighboring keys if necessary
9. optional - dip new key risers in Plasti Dip - it's a rubberized coating available at hardware stores, you use it to coat the handles of pliers and such and it comes in a couple of nifty colors, but black is "classiest"- and allow to dry. Makes it look "professional" (haha) and keeps the funky epoxy smell down.
10. sit back and relax, now you'll play like Trane and Bird. Enjoy your new horn.
OR
go buy some of the rubber "olives" from the music store as described by Carl H. above, put them on your horn. Play like Trane and Bird, but at a fraction of the effort I described above.
dv