Can I donate small amounts to political candidates anonymously?

Today’s mail brought an envelope from the Bernie Sanders for President campaign. I’d like to send him a contribution, but I hesitate for two reasons:

1) I don’t want the campaign to sell my name and address to other candidates and other causes. I don’t want to get a lot of junk mail from groups I have no interest in. Once on a mailing list, you’re tagged for life.

2) I don’t want my name and address to show up on the Federal election Commission web site (and others) where people can look up a city, state, etc., and see who is contributing to who.

Is there a way to give $$ to a political campaign and not show up on these sites and mailing lists?