This is a new guideline from BASHH. It really looks mainly at genital molluscum contagiosum, but some of the evidence is useful for all forms. Basically most patients should be encouraged to just leave them alone as they go naturally within a few months without normally scarring, which is probably what most of us are doing already.
The only treatments with any evidence behind them - and even then the evidence is very limited - are: podophyllotoxin (which can be self-applied) for genital lesions, imiquimod (but not licensed), liquid nitrogen, laser treatment and topical cidofovir (in HIV patients). Interestingly there was a long list of other treatments with no evidence at all behind them.